Econstudentlog

Eating disorders (II)

You can read my first post about the book, which lead to a brief comment exchange which may be of interest to people curious about diagnostics aspects, here. The book has a lot of stuff; in this post I’ll discuss the immune system, covered in chapter 5 of the book, as well as some ways that eating disorders may affect the skin (many of the remaining chapters of the book cover this topic). This will be my last post about the book.

In chapter 5 the authors start out by noting that adequate nutrition is an important factor in terms of maintaining immunocompetence and that malnutrition increases the risk of infection. Quite a few details are known about how specific aspects of nutritional deficiencies affect specific parts of the immune system. When both energy- and protein intake is insufficient (protein-energy malnutrition, PEM) this state of affairs is associated with atrophy of immune organs such as the thymus and spleen, as well as impairments in T cell populations (likely a natural consequence of thymus atrophy – the ‘T’ in ‘T cell’ stands for thymus…). Cytokine prodution (e.g. IL-1, IL-2, interferon-γ) is down-regulated in PEM, and the ability of T cells to respond appropriately to those cytokines is decreased. Impairments in macrophage phagocytotic function and neutrophils have been observed in malnourished individuals.

The authors note in the coverage that there now “seems to be consensus accepting that, overall, the manifestations of the immunocompromised status of ED patients are less frequent and severe than in PEM [3]. In general, the immune function seems to be better preserved than would be expected, considering the highly defective nutritional status of the patients. […] [some of] the most frequent findings described are leukopenia [white blood cell deficiency] with relative lymphocytosis [increased proportion of lymphocytes in the blood], [and] thrombocytopenia [platelet deficiency] […] immunocompetence and particularly T cell subsets are useful tools to follow-up the nutritional status in patients with ED. This asseveration applies also to BN patients, since T cell subsets seem to reflect their subclinical malnutrition, which is not evident from their weight status. […] Vomiting as a purging strategy is associated with a more deleterious effect on T cells […] Complement-system proteins […] have been found decreased in AN [anorexia nervosa] and BN [bulimia nervosa] [6,79] [and] seem to depend also on white adipose tissue mass. […] These proteins might be useful in the follow-up of AN patients, since C3 and C4 falls seem to occur when treated patients resume their restricting habits increasing their risk of relapse [81].”

Despite eating disorders having significant effects on the immune system, infection risk in people with eating disorders seems surprisingly to not be elevated, at least not until an advanced stage of the disease has been reached. There are multiple explanations offered for this observation, but the answer as to why this is is not completely clear. One reason might be that people with eating disorders tend to maintain relatively high protein and vitamin intake in a manner dissimilar from the intake patterns associated with classic starvation, mediating the effects of energy deficiency. Two other reasons offered both relate to the fact that the immune system does not respond normally to pathogens, and so to the extent that symptoms relate to immune responses to infection people with eating disorders have fewer symptoms; this relates to both down-regulation of memory T-cells and suppressed capacity to mount the classic acute-phase response to infection; a reduced febrile response to bacterial infection has been observed in anorexics. In the context of muted responses to infection, the hormone leptin (‘the satiety hormone’) may also be implicated; “there is a function for leptin as an up-regulator factor of inflammatory immune responses. Moreover, leptin production is acutely increased during infection and inflammation […] an impairment in this acute increase in leptin production in AN patients might be related to the lack of infection symptoms in these patients [26].” Interestingly leptin also seems to be downregulated in BN.

Okay, let’s move on and talk a little bit about how eating disorders may affect the skin. The book has a lot of stuff about this so this will not be an exhaustive review of the material covered in the book – but I did think I ought to talk a little bit about this stuff. Skin signs are important in a diagnostic context: “As most patients with eating disorders tend to minimize or even deny their disorder, the skin changes are sometimes the only indication that the patient has an eating disorder.” Some of the skin signs described in the book relate quite directly to specific behaviours (e.g. vomiting in purging subtypes), whereas others are of a more generalized nature and are rather due to the fact that the body does not get enough energy/micronutrients/etc. to handle all the tasks it’s supposed to handle. Some skin signs are considered ‘guiding signs’ of eating disorders, in the sense that they’re signs often found in an eating disorder context but are not usually found in the differential diagnoses natural to consider in the given clinical context, so they can be used as guiding tools in a diagnostic context. Examples of guiding signs include “lanugo-like body hair [very fine, soft, and usually unpigmented, downy hair] due to starvation, Russell’s sign [calluses on the knuckles or back of the hand] and [tooth] enamel erosions due to self-induced vomiting, and self-induced dermatoses due to psychiatric comorbidity.”

Frequent skin signs in eating disorders include dry, scaly skin; orange discolouration of the skin due to excessive consumption of beta carotene (carrots); the aforementioned lanugo-like body hair; coldness of the extremities (feet, toes) and bluish/purplish colouring of the hands and feet, caused by slow circulation (acrocyanosis); hair loss; inflammation of the lips and nail changes. “With a BMI between 17.5 and 16, the skin is usually pale or yellowish and cold, but no specific signs are found.” They note in the book that “Russell sign, dental enamel erosion, and salivary gland enlargement [elsewhere in the coverage they also dub this phenomenon ‘“chipmunk” cheeks of the bulimic’] are pathognomonic of purging behavior”. Dry skin is reported in 70% of people with anorexia nervosa (-AN), and acne is reported in 47–59% of patients – these are very common symptoms/consequences of AN. The same is the case for lanugo; in one study of AN patients (n=62), 77% had lanugo. In one study, alopecia was present in 67% of bulimics (n=122) and 61% of anorexics (n=62).

Observing the hands may be important: “Strumia [1], observing the hand of the patients with anorexia nervosa (AN), noticed that many peculiar skin signs, such as xerosis, acrocyanosis, carotenoderma, evident blood vessels due to decreased subcutaneous tissue, cold hand, nail dystrophy [“Brittle nails affect approximately 30% of patients with anorexia nervosa and bulimia nervosa”], Russell’s sign and artefacta, were located on the hands. Strumia used the term “anorectic’s hand” and suggested that, by examining the hand of a young patient, one can reasonably suspect an eating disorder. Only Russell’s sign is pathognomonic of eating disorders, but at least three signs, excluding Russell’s sign, are required for the diagnosis of “anorectic’s hand”, for example, xerosis, carotenoderma and cold hand. A perspicacious dermatologist should pay attention to this important sign when it appears in young females that show signs of reduced self-esteem and distorted perception of body weight.”

It is noted in the book that classical deficiency syndromes such as scurvy are very rare in AN because “AN is not commonly associated with vitamin deficiencies” – rather it’s the case that many anorectics over-supplement on vitamin supplements, which can paradoxically induce or worsen some skin complaints, such as e.g. xerosis (dry skin).

“the progression of anorexic pathology is accompanied by changing patterns in dietary habits [5]. These patterns include periods of low or no carbohydrate intake and an avoidance of dietary fats. They can also include patterns in which the primary foods consumed are fruits and vegetables. During this period, meat is often avoided. Changes in relative amounts of heavy to light isotopes [of nitrogen] in the hair indicate changes in the body’s metabolic state and dietary intake. […] By definition, individuals with anorexia or anorexia and bulimia are losing weight and do not get adequate nutrition. These individuals get their nitrogen largely from plants, and/or do not get sufficient nitrogen in their diet and are in nitrogen imbalance. By contrast, individuals diagnosed with only bulimia are maintaining their weight, and therefore get adequate nutrition and are likely not to be in nitrogen imbalance. […] Hatch et al. […] suggest that a distinction may be possible between anorexia and bulimia nervosa using 15N/14N and 13C/12C ratios in hair.”

“A reduced pain sensitivity has been found in eating disorder (ED) patients, but it is unclear what physiological and psychological factors are associated with this abnormality.”

January 26, 2016 Posted by | books, medicine | Leave a comment

Prioritization in medicine

This book is not exactly the first book I’ve read on these kinds of topics (see for example my previous coverage of related topics here, here, here, here, here, and here), but the book did have some new stuff and I decided in the end that it was worth blogging, despite the fact that I did not think the book was particularly great. The book is slightly different from previous books I’ve read on related topics because normative aspects are covered in much greater detail – as they put it in the preface:

“This volume addresses normative dimensions of methodological and theoretical approaches, international experiences concerning the normative framework and the process of priority setting as well as the legal basis behind priorities. It also examines specific criteria for prioritization and discusses economic evaluation. […] Prioritization is necessary and inevitable – not only for reasons of resource scarcity, which might become worse in the next few years. But especially in view of an optimization of the supply structures, prioritization is an essential issue that will contribute to the capability and stability of healthcare systems. Therefore, our volume may give useful impulses to face challenges of appropriate prioritization.”

I’m generally not particularly interested in normative questions, preferring instead to focus on the empirical side of things, but the book did have some data as well. In the post I’ll focus on topics I found interesting, and I have made no attempt here to make the coverage representative of the sort of topics actually covered in the book; this is (as usual) a somewhat biased account of the material covered.

The book observes early and often that there’s no way around prioritization in medicine; you can’t not prioritize, because “By giving priority to one group, you ration care to the second group.” Every time you spend a dollar on cancer treatment, well, that’s a dollar you can’t spend on heart disease. So the key question in this context is how best to prioritize, rather than whether you should do it. It is noted in the text that there is a wide consensus that approaching and handling health care allocation rules explicitly is preferable to implicit rationing, a point I believe was also made in Glied and Smith. A strong argument can be made that clear and well-defined decision-rules will lead to better outcomes than implicit allocation decisions made by doctors during their day-to-day workload. The risks of leaving allocation decisions to physicians involve overtaxing medical practitioners (they are implicitly required to repeatedly take decisions which may be emotionally very taxing), problematic and unfair distribution patters of care, and there’s also a risk that such practices may erode trust between patients and physicians.

A point related to the fact that any prioritization decision made within the medical sector, regardless of whether the decision is made implicitly or explicitly, will necessarily affect all patient populations by virtue of the fact that resources used for one purpose cannot be used for another purpose, is that the health care sector is not the only sector in the economy; when you spend money on medicine that’s also money you can’t be spending on housing or education: “The competition between health-related resources and other goods is generally left to a political process. The fact that a societal budget for meeting health needs is the result of such a political process means that in all societies, some method of resolving disagreements about priorities is needed.” Different countries have different approaches to how to resolve these disagreements (and in large countries in particular, lower-level regional differences may also be important in terms of realized care provision allocation decisions), and the book covers systems applied in multiple different countries, including England, Germany, Norway, Sweden, and the US state of Oregon.

Some observations and comments:

“A well-known unfairness objection against conventional cost-effectiveness analysis is the severity of diseases objection – the objection that the approach is blind as to whether the QALYs go to severely or to slightly ill patients. Another is the objection of disability discrimination – the objection that the approach is not blind between treating a life-threatening disease when it befalls a disabled patient and treating the same disease when it befalls a non-disabled patient. An ad hoc amendment for fairness problems like these is equity weighting. Equity weights are multiplication factors that are introduced in order to make some patient group’s QALYs count more than others.”

“There were an estimated 3 million people with diabetes in England in 2009; estimates suggest that the number of people with diabetes could rise to 4.6 million by 2030. There has also been a rapid rise in gastrointestinal diseases, particularly chronic liver disease where the under-65 mortality rate has increased 5-fold since 1970. Liver disease is strongly linked to the harmful use of alcohol and rising levels of obesity. […] the poorest members of the community are at most risk of neglecting their health. This group is more likely to eat, drink and smoke to excess and fail to take sufficient exercise.22 Accordingly, life expectancy in this community is shorter and the years spent of suffering from disability are much longer. […] Generic policies are effective in the sense that aggregate levels of health status improve and overall levels of morbidity and mortality fall. However, they are ineffective in reducing health inequalities; indeed, they may make them worse. The reason is that better-off groups respond more readily to public health campaigns. […] If policy-makers [on the other hand] disinvest from the majority to narrow the inequality gap with a minority resistant to change, this could reduce aggregate levels of health status in the community as a whole. [Health behaviours also incidentally tend to be quite resistant to change in general, and we really don’t know all that much about which sort of interventions work and/or how well they work – see also Thirlaway & Upton’s coverage] […] two out of three adults [in the UK] are overweight or obese; and inequalities in health remain widespread, with people in the poorest areas living on average 7 years fewer than those in the richest areas, and spending up to 17 more years living with poor health. […] the proportion of the total health budget invested in preventive medicine and health promotion […] is small. The UK spends about 3.6 % of its entire healthcare budget on public health projects of this nature (which is more than many other EU member states).”

Let’s talk a little bit about rationing. Rationing by delay (waiting lists) is a well-known method of limiting care, but it’s far from the only way to implicitly ration care in a manner which may be hidden from view; another way to limit care provision is to ration by dilution. This may happen when patients are seen on time (do recall that waiting lists are very common in the medical sector, for very natural reasons which I’ve discussed here on the blog before), but the quality of care that is provided to patients receiving care goes down. Rationing by dilution may sometimes be a result of attempts to limit rationing by delay; if you measure hospitals on whether or not they treat people within a given amount of time, the time dimension becomes very important in the treatment context and it may thus end up dominating other decision variables which should ideally take precedence over this variable in the specific clinical context. The book mentions as an example the Bristol Eye Hospital, where it is thought that 25 patients may have lost their sights because even though they were urgent cases which should have been high priority, they were not treated in time because there was a great institutional focus on not allowing waiting times of any patients on the waiting lists to cross the allowed maximum waiting time, meaning that much less urgent cases were treated instead of the urgent cases in order to make the numbers look good. A(n excessive?) focus on waiting lists may thus limit focus on patient needs, and similar problems pop up when other goals aside from patient needs are emphasized in an institutional context; hospital reorganisations undertaken in order to improve financial efficiency may also result in lower standards of care, and in the book multiple examples of this having happened in a British context are discussed. The chapter in question does not discuss this aspect, but it seems to me likely that rationing by dilution, or at least something quite similar to this, may also happen in the context of a rapid increase in capacity as a result of an attempt to address long waiting lists; if you for example decide to temporarily take on a lot of new and inexperienced nurses to lower the waiting list, these new nurses may not provide the same level of care as do the experienced nurses already present. A similar dynamic may probably be observed in a setting where the number of nurses does not change, but each patient is allocated less time with any given nurse than was previously the case.

“Public preferences have been shown not to align with QALY maximization (or health benefit maximization) across a variety of contexts […] and considerations affecting these preferences often extend well beyond strict utilitarian concerns […] age has been shown to be among the most frequently cited variables affecting the public’s prioritization decisions […] Most people are willing to use age as a criterion at least in some circumstances and at least in some ways. This is shown by empirical studies of public views on priority setting […] most studies suggest that a majority accepts that age can have some role in priority setting. […] Oliver [(2009)] found […] a wide range of context-dependent ‘decision rules’ emerged across the decision tasks that appeared to be dependent on the scenario presented. Respondents referenced reasons including maximizing QALYs,11 maximizing life-years or post-treatment quality of life,12 providing equal access to health care, maximizing health based on perceptions of adaptation, maximizing societal productivity (including familial roles, i.e. ‘productivity ageism’), minimizing suffering, minimizing costs, and distributing available resources equitably. As an illustration of its variability, he noted that 46 of the 50 respondents were inconsistent in their reasoning across the questions. Oliver commented that underlying values influence the respondents’ decisions, but if these values are context dependent, it becomes a challenge – if not impossible – to identify a preferred, overarching rule by which to distribute resources. […] Given the empirical observations that respondents do not seem to rely upon a consistent decision rule that is independent of the prioritization context, some have suggested that deliberative judgments be used to incorporate equity considerations […]. This means that decision makers may call upon a host of different ‘rules’ to set priorities depending on the context. When the patients are of similar ages, prioritization by severity may offer a morally justifiable solution, for example. In contrast, as the age discrepancy becomes greater between the two patients, there may be a point at which ‘the priority view’ (i.e. those who in the most dire conditions take precedence) no longer holds […] There is some evidence that indicates that public preferences do not support giving priority in instances where the intervention has a poor prognosis […] If older patients have poorer health outcomes as a result of certain interventions, [this] finding might imply that in these instances, they should receive lower priority or not be eligible for certain care. […] A substantial body of evidence indicates that the utilitarian approach of QALY maximization fails to adequately capture public preferences for a greater degree of equity into health-care distribution; however, how to go about incorporating these concerns remains unresolved.”

“roughly 35 % of the […] [UK] health expenditures were spent on the 13 % of our population over the age of 65. A similar statistic holds true for the European Union as well […] the elderly, on average, have many more health needs than the non-elderly. In the United States, 23 % of the elderly have five or more chronic health problems, some life-threatening, some quality-of-life diminishing (Thorpe et al. 2010). Despite this statistic, the majority of the elderly in any given year is quite healthy and makes minimal use of the health care system. Health needs tend to be concentrated. The sickest 5 % of the Medicare population consume 39 % of total Medicare expenditures, and the sickest 10 % consume 58 % of Medicare expenditures (Schoenman 2012). […] we are […] faced with the problem of where to draw the line with regard to a very large range of health deficiencies associated with advanced age. It used to be the case in the 1970s that neither dialysis nor kidney transplantation were offered as an option to patients in end-stage kidney failure who were beyond age 65 because it was believed they were not medically suitable. That is, both procedures were judged to be too burdensome for individuals who already had diminished health status. But some centers started dialyzing older patients with good results, and consequently, the fastest growing segment of the dialysis population today (2015) is over age 75. This phenomenon has now been generalized across many areas of surgery and medicine. […] What [many new] procedures have in common is that they are very expensive: $70,000 for coronary bypass surgery (though usually much more costly due to complication rates among the hyper-elderly); $200,000 for the LVAD [Left Ventricular Assist Device]; $100,000+ per month for prolonged mechanical ventilation. […] The average older recipient of an LVAD will gain one to two extra years of life […] there are now (2015) about 5.5 million Americans in various stages of heart failure and 550,000 new cases annually. Versions of the LVAD are still being improved, but the potential is that 200,000 of these devices could be implanted annually in the United States. That would add at least $40 billion per year to the cost of the Medicare program.”

“In the USA, around 40 % of premature mortality is attributed to behavioral patterns,2 and it is estimate[d] that around $1.3 trillion annually — around a third of the total health budget — is spent on preventable diseases.3 […] among the ten leading risk factors contributing to the burden of disease in high-income countries, seven can be directly attributed to unhealthy lifestyles. […] Private health insurance takes such factors into account when calculating premiums for health insurances (Olsen 2009). In contrast, publicly funded health-care systems are mainly based on the so-called solidarity principle, which generally excludes risk-based premiums. However, in some countries, several incentive schemes such as “fat taxes” […], bonuses, or reductions of premiums […] have recently been implemented in order to incorporate aspects of personal responsibility in public health-care systems. […] [An important point in this context is that] there are fundamental questions about whether […] better health leads to lower cost. Among other things, cost reductions are highly dependent on the period of time that one considers. What services are covered by a health system, and how its financing is managed, also matters. Regarding the relative lifetime cost of smokers, obese, and healthy people (never smokers, normal body mass index [BMI]) in the Netherlands, it has been suggested that the latter, and not the former two groups, are most costly — chiefly due to longer life and higher cost of care at the end of life.44 Other research suggests that incentivizing disease management programs rather than broader prevention programs is far more effective.45 Cost savings can therefore not be taken for granted but require consideration of the condition being incentivized, the organizational specifics of the health system, and, in particular, the time horizon over which possible savings are assessed. […] Policies seeking to promote personal responsibility for health can be structured in a very wide variety of ways, with a range of different consequences. In the best case, the stars are aligned and programs empower people’s health literacy and agency, reduce overall healthcare spending, alleviate resource allocation dilemmas, and lead to healthier and more productive workforces. But the devil is often in the detail: A focus on controlling or reducing cost can also lead to an inequitable distribution of benefits from incentive programs and penalize people for health risk factors that are beyond their control.”

January 21, 2016 Posted by | books, economics, medicine | Leave a comment

Oxford Handbook of Clinical Medicine (IV)

Here you can read my first three posts about the book. In this post I’ll talk a little bit about the book’s coverage of surgery; this is a major chapter with a lot of content.

In a surgical context prophylactic antibiotics are very often given to counter the risk of wound infection, especially in the gastrointestinal surgical context. The authors of the chapter don’t discuss the demerits of this approach at all, but I’ve read other people before who are critical of this way of doing things and before moving on to what the book has to say about related matters I thought I should remind you of some of the problems associated with the widespread prophylactic use of antibiotics in the surgical context – here’s part of what Gould and van der Meer had to say about this topic:

“Surgical prophylaxis is a common area of overuse [of antibiotics] as shown in many publications. Measured by total DDDs [defined daily doses], it can amount to around one third of a hospital’s total antibiotic use. This illustrates the potential for ecological damage although surgeons often ask whether 24 h or even single dose prophylaxis can really select for resistance. The simple answer is yes, but of course much of the problem is extension of prophylaxis beyond the perioperative period, often for several days in critical patients, perhaps until all lines and drains are removed. There is no evidence base in favour of such practices.” (link to further blog coverage of related topics here)

Omissions like these is incidentally one of several reasons why I did not give the Oxford handbook a higher rating than I did. With that out of the way let’s get back to the Oxford handbook coverage. They note in the surgery chapter that wound infection occurs in roughly one in five cases of elective GI surgery, and in up to 60 per cent of emergency surgery settings. Infections in surgical patients are not trivial events; they can lead to bleeding, wounds that reopen, and they can ultimately kill the patient. Another major risk associated with surgery in many different surgical contexts is the risk of deep vein thrombosis (-DVT). According to the book DVTs occur in 25-50% of surgical patients. That said, almost two-thirds of below-knee DVTs are asymptomatic and these rarely embolize to the lungs. Aside from surgery some other DVT risk factors worth knowing about include age (older patients are at higher risk), pregnancy, trauma, synthetic oestrogen (i.e., oral contraceptives), past DVT, cancer, obesity, and immobility.

As for DVTs in non-surgical contexts, I found it interesting that the book observes that “the evidence linking air travel to an increased risk of DVT is still largely circumstantial” – it also adds some additional data to contextualize the risk. For someone in the general population, the risk of DVT from a long-distance flight is estimated to be somewhere between one in 10.000 to one in 40.000, however for people in high-risk subgroups the incidence of DVT from flights lasting longer than 10 hours has been estimated at 4-6%. They argue in the book that travelers with multiple risk factors should consider compression stockings and/or a single prophylactic dose of low molecular-weight heparin for flights lasting longer than 6 hours; other ways to minimize risk include leg exercises, increased water intake and refraining from alcohol or caffeine during the flight. “There is no evidence to support the use of prophylactic aspirin.”

Even though I think a common impression is that surgeons always want to cut people open whereas internal medicine people will often think this is not necessary, ‘even surgeons’ are sometimes hesitant to cut you open. There are many reasons for this – the book covers a lot of surgical complications, but a perhaps particularly important long-term problem is this:
“Any surgical procedure that breaches the abdominal or pelvic cavities can predispose to the formation of adhesions [‘Adhesions are fibrous bands[1] that form between tissues and organs, often as a result of injury during surgery. They may be thought of as internal scar tissue that connects tissues not normally connected’], which are found in up to 90% of those with previous abdominal surgery; this is why we do not rush to operate on small bowel obstruction: the operation predisposes to yet more adhesions. Handling of the serosal surface of the bowel causes inflammation, which over weeks to years can lead to the formation of fibrous bands that tether the bowel to itself or adjacent structures […] Their main sequelae are intestinal obstruction (the cause in ~60% of cases […]) and chronic abdominal or pelvic pain.”

Appendicitis is a lot more common than I’d thought; lifetime incidence is 6%, with risk peaking during the second decade of life; according to the book it is the most common surgical emergency. A diagnosis of appendicitis is often wrong; in up to one in five patients a healthy appendix is removed. Another very common surgical procedure is surgical repair of an inguinal hernia; more than 100.000 of these surgeries are performed in the UK each year.

Though the book has a separate chapter specifically dealing with the topic of oncology (and palliative care), the surgical chapter of course also covers various cancers and their treatments. You’ll encounter the usual encouraging remarks about diseases with a ‘gloomy prognosis and non-specific presentation’, ‘[m]ost patients […] present with locally advanced (inoperable) or metastatic disease’ (both quotes are on the topic of carcinoma of the stomach); ‘[s]urvival rates are poor with or without treatment’ (carcinoma of the oesophagus); ‘rare, have an overall poor prognosis and are difficult to diagnose’ (bile duct and gallbladder cancers), ‘~80% present with inoperable disease’ (bile duct cancer). It’s sort of hard to find it encouraging that colorectal carcinoma, another cancer covered in that chapter, in general tend to have lower mortality than these others (“Overall 5yr survival is ~50%”) when you also keep in mind that it’s one of the most common cancers (it is the second most common cause of cancer deaths in the United Kingdom, and the third most common cancer), and so kill a lot more people overall (16.000 deaths/year). Another thing to note is that the survival rate of patients with metastatic disease in this context is still really terrible; the treated 5-year survival rate for patients with distant metastases is reported to be 6.6%, compared to e.g. a 48% survival rate in treated cases with ‘only’ regional lymph node involvement. They observe in their coverage that “[l]aparoscopic surgery has revolutionized surgery for colon cancer. It is as safe as open surgery and there is no difference in overall survival or disease recurrence.”

There are many bodily changes which take place in people as they age, and some of the potentially problematic changes only occasionally cause symptoms despite their presence in a large number of people. One example is gastrointestinal diverticula. These are outpouchings of the gut wall which are present in many people but do not always cause problems. According to the authors, diverticulosis is a term used to indicate that diverticula are present, whereas diverticular disease implies they the diverticula are symptomatic; the term diverticulitis is used when there’s inflammation of the diverticula. 30 % of people at the age of 60 living in the West are estimated to have diverticulosis, but the majority are asymptomatic – they are a common incidental finding when people have colonoscopies. Although they often do not cause problems they can cause perforation and hemorrhage (e.g. large rectal bleeds); the former complication has a high mortality, ~40%. Lack of dietary fiber is thought to be implicated in the pathophysiological processes leading to diverticulosis. Gallstones is another example of a common condition many people have without knowing it; gallstone prevalence is estimated at 8% at the age of 40. Risk is increasing in age and is higher in obese people. 90% remain asymptomatic. Smoking is known to increase the risk that gallstones become symptomatic. Renal stones are also common, with lifetime incidence estimated to be ‘up to’ (?) 15%. However males are three times as likely to get renal stones as are females, so in males in particular these things are very common. In the case of small stones (<5mm in lower ureter) ~90-95 % pass spontaneously on their own. The simplest and easiest way to lower risk of kidney stones is to drink plenty of fluids (but keep in mind that tea increases oxalate levels and thus may contribute to stone formation…). They note that calculi may be asymptomatic but do not provide estimates of how often this is the case; I assume one reason is that it’s really very difficult to get a good estimate of how often people pass stones they did not know they had – you mostly learn about these things when they cause trouble. Making a brief jump back to the topic of cancers it should perhaps be noted that although cancer is not usually thought of as a really not very worrisome asymptomatic condition, some forms of cancer actually sometimes may be just that; autopsy studies have indicated that 80% of men above the age of 80 have some form of prostate cancer.

Stress incontinence is leakage from an incompetent sphincter for example when intra-abdominal pressure rises, which it may do when people laugh or cough. It is very common in pregnancy and following birth, and it “occurs to some degree in ~50% of post-menopausal women”.

Although I didn’t think much of the epidemiology chapter, I did want to include a few observations from the chapter in this post:

“In one study looking at recommendations of meta-analyses where there was a later ‘definitive’ big trial, it turned out that meta-analyses got it wrong 30% of the time”.

“During the time it takes you to read this page, your better-connected patients may have checked out the latest recommendations of Guatemalan Guidelines on Gynaecomastia, or the NICE’S Treatise on Toxoplasmosis. Patients have time and motivation, whereas we have little time and our motivation may be flickering. This can seem threatening to the doctor who sees himself as a dispenser of wisdom and precious remedies. It is less threatening if we consider ourselves to be in partnership with our patients. The evidence is that those who use the internet to question their therapy receive a better service.” (A lot of related topics were incidentally covered in the Cochrane handbook The Knowledgeable Patient: Communication and Participation in Health – see this post for data on and discussion of these things).

 

January 18, 2016 Posted by | books, medicine | Leave a comment

Quotes

i. “The combination of some data and an aching desire for an answer does not ensure that a reasonable answer can be extracted from a given body of data.” (John Tukey)

ii. “Far better an approximate answer to the right question, which is often vague, than an exact answer to the wrong question, which can always be made precise.” (-ll-)

iii. “They who can no longer unlearn have lost the power to learn.” (John Lancaster Spalding)

iv. “If there are but few who interest thee, why shouldst thou be disappointed if but few find thee interesting?” (-ll-)

v. “Since the mass of mankind are too ignorant or too indolent to think seriously, if majorities are right it is by accident.” (-ll-)

vi. “As they are the bravest who require no witnesses to their deeds of daring, so they are the best who do right without thinking whether or not it shall be known.” (-ll-)

vii. “Perfection is beyond our reach, but they who earnestly strive to become perfect, acquire excellences and virtues of which the multitude have no conception.” (-ll-)

viii. “We are made ridiculous less by our defects than by the affectation of qualities which are not ours.” (-ll-)

ix. “If thy words are wise, they will not seem so to the foolish: if they are deep the shallow will not appreciate them. Think not highly of thyself, then, when thou art praised by many.” (-ll-)

x. “Since all models are wrong the scientist cannot obtain a “correct” one by excessive elaboration. On the contrary following William of Occam he should seek an economical description of natural phenomena. Just as the ability to devise simple but evocative models is the signature of the great scientist so overelaboration and overparameterization is often the mark of mediocrity. ” (George E. P. Box)

xi. “Intense ultraviolet (UV) radiation from the young Sun acted on the atmosphere to form small amounts of very many gases. Most of these dissolved easily in water, and fell out in rain, making Earth’s surface water rich in carbon compounds. […] the most important chemical of all may have been cyanide (HCN). It would have formed easily in the upper atmosphere from solar radiation and meteorite impact, then dissolved in raindrops. Today it is broken down almost at once by oxygen, but early in Earth’s history it built up at low concentrations in lakes and oceans. Cyanide is a basic building block for more complex organic molecules such as amino acids and nucleic acid bases. Life probably evolved in chemical conditions that would kill us instantly!” (Richard Cowen, History of Life, p.8)

xii. “Dinosaurs dominated land communities for 100 million years, and it was only after dinosaurs disappeared that mammals became dominant. It’s difficult to avoid the suspicion that dinosaurs were in some way competitively superior to mammals and confined them to small body size and ecological insignificance. […] Dinosaurs dominated many guilds in the Cretaceous, including that of large browsers. […] in terms of their reconstructed behavior […] dinosaurs should be compared not with living reptiles, but with living mammals and birds. […] By the end of the Cretaceous there were mammals with varied sets of genes but muted variation in morphology. […] All Mesozoic mammals were small. Mammals with small bodies can play only a limited number of ecological roles, mainly insectivores and omnivores. But when dinosaurs disappeared at the end of the Cretaceous, some of the Paleocene mammals quickly evolved to take over many of their ecological roles” (ibid., pp. 145, 154, 222, 227-228)

xiii. “To consult the statistician after an experiment is finished is often merely to ask him to conduct a post mortem examination. He can perhaps say what the experiment died of.” (Ronald Fisher)

xiv. “Ideas are incestuous.” (Howard Raiffa)

xv. “Game theory […] deals only with the way in which ultrasmart, all knowing people should behave in competitive situations, and has little to say to Mr. X as he confronts the morass of his problem. ” (-ll-)

xvi. “One of the principal objects of theoretical research is to find the point of view from which the subject appears in the greatest simplicity.” (Josiah Williard Gibbs)

xvii. “Nothing is as dangerous as an ignorant friend; a wise enemy is to be preferred.” (Jean de La Fontaine)

xviii. “Humility is a virtue all preach, none practice; and yet everybody is content to hear.” (John Selden)

xix. “Few men make themselves masters of the things they write or speak.” (-ll-)

xx. “Wise men say nothing in dangerous times.” (-ll-)

 

 

January 15, 2016 Posted by | biology, books, Paleontology, quotes/aphorisms, statistics | Leave a comment

A few lectures

Below are three new lectures from the Institute of Advanced Study. As far as I’ve gathered they’re all from an IAS symposium called ‘Lens of Computation on the Sciences’ – all three lecturers are computer scientists, but you don’t have to be a computer scientist to watch these lectures.

Should computer scientists and economists band together more and try to use the insights from one field to help solve problems in the other field? Roughgarden thinks so, and provides examples of how this might be done/has been done. Applications discussed in the lecture include traffic management and auction design. I’m not sure how much of this lecture is easy to follow for people who don’t know anything about either topic (i.e., computer science and economics), but I found it not too difficult to follow – it probably helped that I’ve actually done work on a few of the things he touches upon in the lecture, such as basic auction theory, the fixed point theorems and related proofs, basic queueing theory and basic discrete maths/graph theory. Either way there are certainly much more technical lectures than this one available at the IAS channel.

I don’t have Facebook and I’m not planning on ever getting a FB account, so I’m not really sure I care about the things this guy is trying to do, but the lecturer does touch upon some interesting topics in network theory. Not a great lecture in my opinion and occasionally I think the lecturer ‘drifts’ a bit, talking without saying very much, but it’s also not a terrible lecture. A few times I was really annoyed that you can’t see where he’s pointing that damn laser pointer, but this issue should not stop you from watching the video, especially not if you have an interest in analytical aspects of how to approach and make sense of ‘Big Data’.

I’ve noticed that Scott Alexander has said some nice things about Scott Aaronson a few times, but until now I’ve never actually read any of the latter guy’s stuff or watched any lectures by him. I agree with Scott (Alexander) that Scott (Aaronson) is definitely a smart guy. This is an interesting lecture; I won’t pretend I understood all of it, but it has some thought-provoking ideas and important points in the context of quantum computing and it’s actually a quite entertaining lecture; I was close to laughing a couple of times.

January 8, 2016 Posted by | Computer science, economics, Game theory, Lectures, mathematics, Physics | Leave a comment

Quotes

i. “The educated don’t get that way by memorizing facts; they get that way by respecting them.” (Tom Heehler)

ii. “The things you think about determine the quality of your mind. Your soul takes on the color of your thoughts.” (Marcus Aurelius)

iii. “There is no man so fortunate that there shall not be by him when he is dying some who are pleased with what is going to happen.” (-ll-)

iv. “Most of what we say and do is not necessary, and its omission would save both time and trouble. At every step, therefore, a man should ask himself, ‘Is this one of the things that are superfluous?’.” (Marcus Aurelius, as quoted in Bill Gillham’s book Case Study Research Methods, page 97)).

v. “statistics only lie to those who don’t understand them.” (Bill Gillham, Case Study Research Methods, page 80).

vi. “Few know the joys that spring from a disinterested curiosity. It is like a cheerful spirit that leads us through worlds filled with what is true and fair, which we admire and love because it is true and fair.” (John Lancaster Spalding)

vii. “The teacher does best, not when he explains, but when he impels his pupils to seek themselves the explanation.” (-ll-)

viii. “As our power over others increases, we become less free; for to retain it, we must make ourselves its servants.” (-ll-)

ix. “They who truly know have had to unlearn hardly less than they have had to learn.” (-ll-)

x. “They who no longer believe in principles still proclaim them, to conceal, both from themselves and others, the selfishness of the motives by which they are dominated.” (-ll-)

xi. “When we have not the strength or the courage to grasp a new truth, we persuade ourselves that it is not a truth at all.” (-ll-)

xii. “We neglect the opportunities which are always present, and imagine that if those that are rare were offered, we should put them to good use. Thus we waste life waiting for what if it came we should be unprepared for.” (-ll-)

xiii. “The inclination to seek the truth is safer than the presumption which regards unknown things as known.” (Augustine of Hippo)

xiv. “It is no advantage to be near the light if the eyes are closed.” (-ll-)

xv. “The true test of intelligence is not how much we know how to do, but how we behave when we don’t know what to do.” (John Holt)

xvi. “The most important thing any teacher has to learn […] can be expressed in seven words: Learning is not the product of teaching. Learning is the product of the activity of learners.” (-ll-)

xvii. “It is not just power, but impotence, that corrupts people. It gives them the mind and soul of slaves. It makes them indifferent, lazy, cynical, irresponsible, and, above all, stupid.” (-ll-)

xviii. “No man ever became extremely wicked all at once.” (Juvenal)

xix. “those who live in the West or in middle-class urban enclaves in the Non-west […] have to make a determined effort to grasp the grimness of past reality for most of humankind. In non-privileged, non-modern societies, most people in times past were malnourished, inadequately clothed against the elements, unwashed and filthy, living with insect parasites in overcrowded hovels. […] In these circumstances, “ill-health” […] very often simply meant that one was too incapacitated to carry on working in the fields or in the shop. It did not mean that one woke up feeling slightly off-color […] in the world we have lost, feeling somewhat off-color (or worse) was the standard condition.” (Disease and Medicine in World History, by Sheldon Watts, pp. 9-10).

xx. “In pre-modern China […] the task of establishing standard medical-related interpretations and texts was undertaken largely by philosophers and other scholars intent on building up grand systems which explained everything in the universe. Given that purpose, they did not attempt to build systems based on knowledge of the organs in an actual human body. […] At least until the mid-eighteenth century CE, well-known medico-philosophers [in China] wove the concept of “demon” as disease-cause-to-be-cleansed-away-by-exorcism into textual interpretations of what actually caused disease and what should be done about it.” (ibid., pp. 70, 72).

January 7, 2016 Posted by | quotes/aphorisms | Leave a comment

Eating disorders… (I)

“Dermatologists have an important role in the early diagnosis of eating disorders since skin signs are, at times, the only easily detectable symptoms of hidden anorexia and bulimia nervosa. Forty cutaneous signs have been recognized”

The full title of the book is Eating Disorders and the Skin, but there’s a lot of stuff about eating disorders in general in this book as well, and I figured I’d mostly focus on the ‘general stuff’ in this post. Here’s my goodreads review of the book, which I gave 3 stars.

Here are the DSM-IV-TR diagnostic criteria for anorexia nervosa:

“1. Refusal to maintain body weight at or above a minimally normal weight for age and height (e.g., weight loss leading to maintenance of body weight less than 85% of that expected, or failure to make expected weight gain during period of growth, leading to body weight less than 85% of that expected).

2. Intense fear of gaining weight or becoming fat even though underweight.

3. Disturbance in the way in which one’s body weight or shape is experienced, undue influence of body weight or shape on self-evaluation, or denial of the seriousness of the current low body weight.

4.4. In postmenarcheal females, amenorrhea, i.e., the absence of at least three consecutive menstrual cycles.”

Interestingly, aside from anorexia [-AN] and bulimia [-BN] (diagnostic criteria here), there’s also a big category called ED-NOS – Eating Disorder Not Otherwise Specified. That’s for cases that don’t really fit into the standard criteria for specific eating disorders; they note than an example of this type could be a female fitting all diagnostic criteria for AN except that she has regular menses. It is perhaps worth mentioning here that surprisingly enough (…to me), menstrual irregularities are not limited to cases of AN, thus: “In almost 50% of bulimic patients, menstrual irregularities, such as oligomenorrhea or amenorrhea, take place”. They note in the book that there’s been some concern about the validity of the ED-NOS category, which makes up almost 60% of patients with an eating disorder. Eating disorders are much more common in females than in males (“Males are generally reported to account for 5–10% of anorectics and 10–15% of bulimics identified in the general population”), and particular subgroups mentioned to be at high risk are athletes, models and dancers. It’s noted in the book that most epidemiological studies are conducted in high-risk settings, whereas epidemiological studies assessing risk in the general population are somewhat rarer. One problem complicating matters a little in terms of estimating risk is that an eating disorder cannot be diagnosed through a self-report questionnaire; you need a structured or semi-structured interview to make a diagnosis, which makes things more expensive. As in other contexts one way to get around this issue, at least to some extent, is to employ multi-step screening protocols – in this case a two-step procedure in which individuals at high risk are identified at the first step through inexpensive means, and these individuals are then later assessed more carefully in the second step, employing more accurate (and expensive) methods.

They note that in Western countries, point prevalence of AN in female adolescent (the highest risk sub-group) is estimated at 0.2-1% of the population, whereas the prevalence studies on bulimia nervosa indicates that this eating disorder is somewhat more common, with the majority of studies finding prevalences of 1.5-5%; do recall again that most studies as already mentioned look at high-risk subgroups, so total population prevalence is likely to be lower than this. They observe in the book that general-practice studies find that the incidence of anorexia nervosa is less than one in ten-thousand per year (8 per 100,000 per year); so full-blown AN certainly is likely quite rare in low-risk populations.

On lifetime risk, the book notes that:

“Most of the epidemiological studies on ED [eating disorders] have evaluated the prevalence of full syndromes of both AN [anorexia nervosa] and BN [bulimia nervosa]. The few studies that have evaluated partial or subclinical manifestations of EDs in young females, however, found lifetime prevalence rates of 5–12% for atypical AN and 1–4.8% for atypical BN and up to 14.6% in adolescent samples”.

A review of epidemiological studies concluded that there’s no evidence of either a secular increase in AN or BN over time; to the extent that the number of people with diagnosed BN has increased over time, changes in diagnostic and referral practices likely account for this. On a related topic it is noted in the book that “It is a common idea among clinicians that early-onset cases of anorexia nervosa (AN) are increasing, but few data in the literature are available to demonstrate this trend.”

AN most commonly present among females at the age of 15-19, whereas BN presents a little later, most commonly at the age of 20-24. But eating disorders are not limited to teenagers and young adults: “Even if anorexia nervosa and bulimia nervosa occur characteristically in females during adolescence and young adulthood, there have been case reports of illness beginning after the age of 25 and even after the menopause, and some authors suggest that the rates of eating disorders in older patients may be increasing [2]. Clinical impression suggests that the late-onset cases present with more depressive features than the adolescent counterpart. […] dieting is considered one of the most salient precipitating factors.”

Self-report metrics can only help you so much when you’re trying to assess risk; a major problem in this context is that denial of illness is a very common feature in these patient populations (so you certainly can’t just ask people if their relationship with food/exercise etc. might be unhealthy…): “typically, [the] course [of an eating disorder] is characterized by a high fluidity between the diagnostic classes; furthermore, the patient often denies even to himself the psychiatric nature of the disease” (recall also that “denial of the seriousness of the current low body weight” is included in the diagnostic criteria). The book covers a lot of symptoms which relate to low body weight – like cold intolerance, bradycardia (slow heart rate), acrocyanosis (bluish discoloration of the hands and feet, caused by slow circulation), systemic hypotension (low blood pressure), lots of skin signs (I haven’t decided yet how much detail I’ll go into, so let’s leave it at that now) – or e.g. to purging behaviours (throat and tooth pain due to vomiting and enamel erosion), but it would go much too far to discuss all these in detail here. One to me interesting aspect of the coverage was that whereas BMI is a useful sign, it’s not itself a diagnostic criterion; the authors note that a BMI below 18.5 is considered pathological, but when listing main signs of anorexia nervosa the most important diagnostic sign (or at least the first one listed) is a BMI below 17.5; I assume part of the discussion surrounding the validity of the ED-NOS category probably relate to individuals who’re in this ‘border area’; they likely have some symptoms due to low body mass (like e.g. cold intolerance), but they don’t have full-blown AN (there are a lot of things that can go wrong when you have low body mass – there are a lot of symptoms described in this book!). It’s also important to note that very different symptom patterns can be present at similar levels of BMI, as the severity of symptoms also relate to how fast body mass decreases – the body is actually capable of adjusting quite well to lower energy intake states (in the short run at least), and so “if weight loss is gradual, it is possible to maintain, even for a long time, an apparent metabolic equilibrium.”

Anorexics have high mortality rates: “From a meta-analysis of 119 studies involving 5,590 patients, Steinhausen reported a crude mortality rate of 5% which exceeded 9% in a followup of 10 years.” Remember when thinking about those estimates that most of the people in these studies were likely young women – these numbers are high, and the authors note that anorexia nervosa “represents the major cause of death of young women in the age between 12 and 25 years.”

Most deaths are due to ventricular arrhythmia; the book goes into some detail about how anorexia affects the cardiovascular system, but I won’t discuss this in detail. An important observation is that: “Cardiac findings tend to disappear with weight recovery.” I assume this comment relates mostly to findings like QTc prolongation, QTc dispersion, and mitral valve prolapse, all of which are found in anorexics, whereas I’d be surprised if cardiac abnormalities related to direct damage to the heart muscle resolve themselves after weight gain, but the book does not go into details on this topic, except in the sense that it is noted that heart failure is uncommon in anorexics. Among those who survive their illness, osteoporosis is a major irreversible long-term problem. People with higher body mass tend to have a higher bone mineral density and thus a lower risk of osteoporosis (unless they get type 2 diabetes, in which case the situation is, well, complicated), so perhaps it’s not really surprising that women with AN and very low body mass index tend to develop osteoporosis. They certainly do:

“Osteopenia and osteoporosis represent one of the most relevant and potentially not reversible complications of eating disorders. This complication is particularly severe when eating disorders have an early onset […] Bone loss is an early effect of the disease, already present after 6–12 months […] In untreated patients, bone loss ranges from 4% up to 10% per year […]. In case of recovery, the progressive loss of BMD [bone mineral density] stops, but in most cases, a normal bone mass is not restored [64].”

It’s noted that bone loss is due to both hormonal and metabolic factors; estrogen plays a role, and “BMD loss in AN is more rapid and severe than in other hypoestrogenic conditions”. Despite this observation weight gain is considered the primary treatment modality of osteoporosis in this context (i.e., not estrogen therapy), and research using estrogen therapy to try to boost bone mineral density in anorexics who did not also gain weight has not been successful.

A to me interesting aspect of the coverage which I could not help but discuss here is how eating disorders relate to diabetes; the book has a few remarks on this topic:

“The concurrence of an eating disorder with insulin-dependent diabetes has been outlined by several researchers: especially bulimia nervosa and disorder not otherwise specified (EDNOS) are reported to be significantly higher in females with type 1 diabetes […] In case of comorbidity, ED onset followed the diagnosis of IDDM in 70% of the patients [10]. Specific aspects of diabetes and its management could, in fact, potentially increase a particular susceptibility to the development of an eating disorder: weight gain, associated with initiation of insulin treatment and dietary restraint, might, in fact, trigger body dissatisfaction and the drive for thinness with consequent weight control behaviors ranging from healthy to very unhealthy behaviors […] insulin omission [is] a common weight loss behavior in girls with IDDM and eating disorder […] APA Guidelines 2006 suggest that insulin omission should be considered a specific type of purging behavior in the next DSM revision”.

I don’t know if this suggested change has been implemented at this point, but it would make a lot of sense. To people who don’t know what this ‘insulin omission’ they talk about is all about, the short version is that if you’re a type 1 diabetic in need of regular insulin injections, if you don’t take enough insulin you lose weight and you can eat pretty much whatever you like without gaining weight; which is of course an unfortunate though likely very attractive option for young women to have. The downside of engaging in systematic insulin omission behaviour of that kind is that you’ll likely go blind from your diabetes and/or die of kidney failure or DKA if you do that for an extended period of time.

January 2, 2016 Posted by | books, diabetes, medicine, Psychology | 4 Comments

Books 2015

Below I have posted a list of books I’ve read to completion in 2015, as well as links to blog posts covering the books and reviews of the books which I’ve written on goodreads. At the bottom of the post I have also added the books I did not finish this year, as well as some related links and comments. If you want ‘the big picture’, goodreads has made a very nice ‘my year in books‘ collection with covers and ratings of the books, as well as a few summary statistics. The goodreads overview also includes books I did not read in full, which is why the number of books included in that overview (160) is higher than the number of books on the list below.

Before I move on to the list, I want to talk a little bit about what’s on it and add some data – people who just want to peruse the list of books and links are welcome to skip the next few paragraphs, though I do believe they add some relevant context which might be of interest.

The major change (which isn’t really all that ‘major’, to be honest…) to this year’s list, compared to the 2014 book list, is the inclusion of an additional category, the ‘t/m’ (travel/miscellaneous) category. The other two categories on the list are fiction (-f) and non-fiction (-nf). According to the goodreads overview to which I linked above, I read 44,892 pages in 2015 (~123 pages/day), and the average page count of the books I read was 284. During the year I finished 153 books, which translates into roughly 3 books per week, with one of those three books (51 books altogether) being what I might term ‘serious non-fiction’. There are 10 books in the travel/miscellaneous category and most of these are categorized as non-fiction on sites like goodreads, so the number of non-fiction books depends a bit on how you categorize these things – if I had not added the new travel/miscellaneous category the number of non-fiction books might have been close to 60, but I did not like that categorization model because it seemed to me to lump together books which I did not really think ‘belonged together’. As it is, roughly 40% of all non-fiction books I read (20 books) were published by Springer or Oxford University Press, with most of the remainder being publications from other academic publishers. It should perhaps be noted in this context that although most of the books in the miscellaneous category are light reading, the category does also include Scott’s Last Expedition, an ~850 pages long book on which I spent roughly 25 hours (that one I for a while strongly considered moving to the non-fiction category).

Since I use categories quite systematically when covering non-fiction books on the blog, I decided to use these categories to get a handle on which topics I’ve read about during the year. It turns out that I have posted 20 posts about books dealing with both the topics of medicine and psychology. I posted 12 posts about books dealing with the topic of diabetes, 8 posts about books dealing with the topic of biology, and 7 about books dealing with the topic of statistics. Minor categories include economics (6 posts each), mathematics and zoology (5 posts each), as well as cancer, evolution, alcohol, and anthropology (4 posts each). In terms of books I’ve covered, I have covered 11 books about psychology, 10 books about medicine, and 9 books about diabetes. Other key topics include mathematics and statistics (5 books each), and economics and biology (4 books each).

Although I did cover the majority of the non-fiction books I read during the year on the blog, there is a substantial proportion of books which I either only reviewed on goodreads or did not review at all; the counts above do not include the topics covered in these 21 books, so although the count is an accurate representation of the sort of posts you may find on the blog, they may not be an accurate representation of the sort of books I read during the year; some books are easier to blog than others. I tried to informally estimate the magnitude of this implicit selection bias by trying to figure out which categories I might have used had I found the time to blog the non-fiction books I did not get around to blogging this year; you can probably quibble over the details in one or two cases, but in most cases it seemed reasonably easy for me to figure out which main categories I would have used in connection with a specific book – it doesn’t take a lot of work to realize that a book named ‘Prioritization in Medicine’ would probably be categorized as ‘medicine’, or that a history book would go into the ‘history’ bin. According to my count, among books not included in the count above there were 6 books which I think I would have blogged under the ‘medicine’ category, 6 I would have blogged under the ‘psychology’ category, 5 books about statistics and 4 books I would have categorized under ‘history’. The remaining categories which I considered it likely I would have used were biology and physics (2 each), and philosophy and linguistics (1 each); the implicit posting bias doesn’t appear to be too bad, though it does look as if books on statistics in particular seem, not surprisingly (to me), to be less likely than other books to ‘get a blog post’, rather than a goodreads review (there were few non-fiction books which I did not either blog or review on goodreads). This makes sense because stats posts tend to take a lot of time to write, so I don’t find it surprising that I only ended up blogging half of the 10 statistics books I finished this year. A related reason is probably that a few of those books covered topics I have already covered here on the blog; I have for example already read multiple epidemiology textbooks at this point, and if the book doesn’t add much new stuff I see no reason to blog it.

It should be noted that the above numbers are ‘subject to change’ because there are still some books I read in 2015 which I would like to blog later on, and so what’ll happen in 2016 is that I’ll add more links over time to this post until it covers all the posts and books I want to cover, but I’ll leave the outline above the way it was at the time I wrote this post as it would be a lot of work to modify all the relevant numbers above every time I add a new blog post to this link collection.

I don’t blog fiction these days, but given how much fiction I’m reading at the moment I probably should add a few comments on that topic as well. 2015 was the year I discovered P. G. Wodehouse; a clear majority of the fiction books I read this year (61 books) were written by Wodehouse. I also read 13 books by Agatha Christie; the remainder of my fiction reading was spread out over quite a few authors.

Before moving on to the list I should of course mention that recommendations are always welcome and that I’m always curious to know which kinds of books other people are reading…

The list of books I finished:

1. The Last Dragonslayer (f). Jasper Fforde. Short goodreads review here.

2. The Song of the Quarkbeast (f). Jasper Fforde. Short goodreads review here.

3. The Eye of Zoltar (f). Jasper Fforde.

4. Statistical Models for Proportions and Probabilities (nf. Springer). Blog coverage here.

5. Negotiation Theory and Research (2, nf. Psychology Press). Goodreads review here. Blog coverage here, here, and here.

6. The Cyberiad (3, f). Stanislaw Lem. Goodreads review here.

7. Chamberlain’s Symptoms and Signs in Clinical Medicine: An Introduction to Medical Diagnosis (4, nf. CRC Press). Blog coverage here, here, here, and here.

8. Diabetes: The Biography (5, nf. Oxford University Press). My goodreads review is worth reposting here: “This book is awesome. This is simply a wonderful account of the history of diabetes. Highly recommended.” Blog coverage here.

9. Lord of the Flies (2, f). William Golding. Short goodreads review here.

10. Model Selection and Multi-Model Inference: A Practical Information-Theoretic Approach (5, nf. Springer). Goodreads review here. Blog coverage here and here.

11. Recountings: Conversations with MIT Mathematicians (4, nf. AK Peters). Blog coverage here.

12. Whose Body? (2, f). Dorothy Sayers.

13. Clouds of Witness (3, f). Dorothy Sayers.

14. Introduction to Systems Analysis: Mathematically Modeling Natural Systems (3, nf. Springer). Note that goodreads has listed this book under the wrong title, which is the reason why the title in this post deviates from the title on goodreads. Goodreads review here. Blog coverage here.

15. Unnatural Death (2, f). Dorothy Sayers.

16. Mammoths, Sabertooths, and Hominids: 65 Million Years of Mammalian Evolution in Europe (4, nf. Columbia University Press). Blog coverage here, here, and here.

17. Belief-Based Stability in Coalition Formation with Uncertainty: An Intelligent Agents’ Perspective (2, nf. Springer). Blog coverage here.

18. Lord Peter Views the Body (2, f). Dorothy Sayers.

19. Something Fresh (5, f). P. G. Wodehouse. Blog coverage here.

20. Leave It to Psmith (5, f). P. G. Wodehouse.

21. Summer Lightning (5, f). P. G. Wodehouse.

22. The Psychology of Lifestyle: Promoting Healthy Behaviour (2, nf. Routhledge). Blog coverage here, here, and here.

23. Blandings Castle and Elsewhere (3, f). P. G. Wodehouse.

24. Thank You, Jeeves (5, f). P. G. Wodehouse.

25. Right Ho, Jeeves (5, f). P. G. Wodehouse.

26. The Code of the Woosters (4, f). P. G. Wodehouse.

27. Uncle Fred in the Springtime (5, f). P. G. Wodehouse.

28. The Inimitable Jeeves (3, f). P. G. Wodehouse.

29. A Damsel in Distress (4, f). P. G. Wodehouse.

30. Full Moon (5, f). P. G. Wodehouse.

31. Cocktail Time (5, f). P. G. Wodehouse.

32. Big Money (4, f). P. G. Wodehouse. Blog coverage here.

33. Picadilly Jim (5, f). P. G. Wodehouse.

34. Ukridge (1, f). P. G. Wodehouse. Short goodreads review here.

35. A Systematic Review of Key Issues in Public Health (1, nf. Springer). Goodreads review here. Blog coverage here and here.

36. Meet Mr. Mulliner (2, f). P. G. Wodehouse.

37. The Hungry Mind: The Origins of Curiosity in Childhood (2, nf. Harvard University Press). Short goodreads review here. Blog coverage here and here.

38. Care Giving for Alzheimer’s Disease – A Compassionate Guide for Clinicians and Loved Ones (1, nf. Springer). Goodreads review here.

39. Money for Nothing (3, f). P. G. Wodehouse.

40. The Small Bachelor (3, f). P. G. Wodehouse.

41. Neither here Nor there: Travels in Europe (5, t/m. Black Swan). Bill Bryson. This book is very funny!

42. The Lost Continent: Travels in Small-town America (2, t/m. Black Swan). Bill Bryson.

43. Life on a Young Planet: The First Three Billion Years of Evolution on Earth (3, nf. Princeton University Press).

44. Notes from a Small Island (2, t/m. Black Swan). Bill Bryson.

45. Laughing Gas (4, f). P. G. Wodehouse.

46. A Pelican at Blandings (3, f). P. G. Wodehouse.

47. Young Men in Spats (4, f). P. G. Wodehouse. Short goodreads review here.

48. Providing Practical Support For People With Autism Spectrum Disorders: Supported Living In The Community (2, nf. Jessica Kingsley Publishers). Short goodreads review here. Blog coverage here.

49. The Clicking of Cuthbert (2, f). P. G. Wodehouse. Goodreads review here.

50. Night Watch (5, f). Terry Pratchett. “In my opinion this is one of Pratchett’s best books” – from my goodreads review. I added the book to my list of favourite books on goodreads.

51. Notes from a big country (3, t/m. Black Swan). Bill Bryson. Short goodreads review here.

52. Idle Thoughts of an Idle Fellow (3, f). Jerome K. Jerome. Goodreads review here.

53. Down Under (4, t/m. Black Swan). Bill Bryson.

54. Routhledge Handbook of Civil Wars (3, nf. Routhledge). Blog coverage here, here, and here.

55. The Complete Yes Minister (5, f). Jonathan Lynn & Anthony Jay.

56. Three Men in a Boat (2, t/m). Jerome K. Jerome. Goodreads review here.

57. Pigs Have Wings (4, f). P. G. Wodehouse.

58. Three Men on the Bummel (3, t/m). Jerome K. Jerome. Goodreads review here.

59. Service With a Smile (5, f). P. G. Wodehouse. Short goodreads review here.

60. Summer Moonshine (3, f). P. G. Wodehouse.

61. Practical Approaches to Causal Relationship Exploration (nf. Springer). Goodreads review here.

62. Quick service (3, f). P. G. Wodehouse.

63. Spring Fever (4, f). P. G. Wodehouse.

64. Chronic Depression: Interpersonal Sources, Therapeutic Solutions (2, nf. American Psychological Association). Short goodreads review here. Blog coverage here and here.

65. The Swoop (1, f). P. G. Wodehouse. Short goodreads review here.

66. Money in the Bank (4, f). P. G. Wodehouse.

67. A Walk in the Woods: Rediscovering America on the Appalachian Trail (3, t/m. Anchor Books). Bill Bryson.

68. The Prince and Betty (3, f). P. G. Wodehouse.

69. The Girl on the Boat (4, f). P. G. Wodehouse. Goodreads review here.

70. The System of Nature, Vol. 1 (nf.). Paul-Henri Thiry d’Holbach. Goodreads review here.

71. Made in America: An Informal History of the English Language in the United States (3, nf. Avon Books). Goodreads review here.

72. Jill the Reckless (2, f). P. G. Wodehouse. Short goodreads review here.

73. Indiscretions of Archie (3, f). P. G. Wodehouse. Short goodreads review here.

74. The Gem Collector (3, f). P. G. Wodehouse.

75. Photosynthesis in the Marine Environment (4, nf. Wiley-Blackwell). Short goodreads review here. Blog coverage here, here, and here.

76. A Prefect’s Uncle (1, f). P. G. Wodehouse. Short goodreads review here.

77. Clocks in the Sky: The story of pulsars (3, nf. Springer). Goodreads review here.

78. A Judgement in Stone (2, f). Ruth Rendell. Goodreads review here.

79. Psmith in the City (3, f). P. G. Wodehouse. Short goodreads review here.

80. Psmith, journalist (3, f). P. G. Wodehouse. Short goodreads review here.

81. Psychological Aspects of Cyberspace: Theory, Research, Applications (2, nf. Cambridge University Press). Goodreads review here.

82. Partner Violence: A New Paradigm for Understanding Conflict Escalation (1, nf. Springer). Goodreads review here. Blog coverage here and here.

83. The Importance of Being Earnest (3, f). Oscar Wilde.

84. An Ideal Husband (3, f). Oscar Wilde. Short goodreads review here.

85. Applied Methods of Cost-Effectiveness Analysis in Healthcare (Handbooks in Health Economic Evaluation) (5, nf. Oxford University Press). Blog coverage here, here, and here.

86. Joy in the Morning (5, f). P. G. Wodehouse.

87. Managing Self-Harm: Psychological Perspectives (1, nf. Routhledge). Goodreads review here.

88. The Mating Season (4, f). P. G. Wodehouse.

89. Cognitive Psychology: A Student’s Handbook (3, nf. Psychology Press). This book is long and takes a significant amount of time to read. Blog coverage here.

90. Jeeves in the Offing (4, f). P. G. Wodehouse.

91. Stiff Upper Lip, Jeeves (5, f). P. G. Wodehouse.

92. Waves (The MIT Press Essential Knowledge Series) (3, nf. MIT Press).

93. Jeeves and the Feudal Spirit (4, f). P. G. Wodehouse.

94. Much Obliged, Jeeves (4, f). P. G. Wodehouse.

95. The Adventures of Tom Sawyer (3, f). Mark Twain. Short goodreads review here.

96. Loneliness: Human Nature and the Need for Social Connection (2, nf. W. W. Norton & Company). Blog coverage here, here, and here.

97. Heavy Weather (5, f). P. G. Wodehouse. Short goodreads review here.

98. Lord Emsworth and Others (3, f). P. G. Wodehouse. Goodreads review here.

99. Carry on, Jeeves (5, f). P. G. Wodehouse. Goodreads review here.

100. On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life (nf.). Charles Darwin. Blog coverage here.

101. Galahad at Blandings (5, f). P. G. Wodehouse.

102. Nothing Serious (2, f). P. G. Wodehouse. Short goodreads review here.

103. Epidemiology Matters: A New Introduction to Methodological Foundations (2, nf. Oxford University Press). Goodreads review here.

104. Bring on the Girls (5, t/m). P. G. Wodehouse and Guy Bolton. Goodreads review here.

105. The Hippopotamus (4, f). Stephen Fry. Goodreads review here.

106. Band of Brothers: E Company, 506th Regiment, 101st Airborne from Normandy to Hitler’s Eagle’s Nest (2, nf. Pocket Books/Stephen Ambrose). Goodreads review here.

107. Snuff (4, f). Terry Pratchett. Goodreads review here.

108. Simply Rational: Decision Making in the Real World (4, nf. Oxford University Press). Goodreads review here. This SSC comment includes a few quotes from the book.

109. Mathematically Speaking: A Dictionary of Quotations (2, nf. Taylor & Francis Group). Goodreads review here. Blog coverage here.

110. The Luck of the Bodkins (4, f). P. G. Wodehouse.

111. Plum Pie (4, f). P. G. Wodehouse. Goodreads review here.

112. The Man With Two Left Feet, and Other Stories (4, f). P. G. Wodehouse. Goodreads review – including some spoilers – here.

113. The Nature of Statistical Evidence (Lecture Notes in Statistics) (3, nf. Springer). Goodreads review here. Blog coverage here.

114. Understanding Other-Oriented Hope: An Integral Concept Within Hope Studies (1, nf. Springer). Goodreads review here. Blog coverage here.

115. Emotion and Reasoning (2, nf. Psychology Press). Goodreads review here.

116. Peripheral Neuropathy & Neuropathic Pain: Into the light (5, nf. Tfm Pub Ltd). Blog coverage here and here.

117. The Adventures of Sally (4, f). P. G. Wodehouse.

118. Flowers for Algernon (4, f). Daniel Keyes. Goodreads review here.

119. Love Among the Chickens (3, f). P. G. Wodehouse. Short goodreads review here.

120. Oxford Handbook of Clinical Medicine (3, nf. Oxford University Press). Very long (~900 pages of content), takes a lot of time to read. Blog coverage here, here, here, and here.

121. The Man Upstairs and Other Stories (3, f). P. G. Wodehouse.

122. Effects of Antidepressants (2, nf. InTech). Blog coverage here.

123. Scott’s Last Expedition (Classics of World Literature) (4, t/m. Wordsworth Editions). Long (848 pages). Goodreads review here.

124. Hot Water (4, f). P. G. Wodehouse.

125. Principles of Applied Statistics (5, nf. Cambridge University Press). Goodreads review here. Blog coverage here.

126. The Girl in Blue (4, f). P. G. Wodehouse. Short goodreads review here.

127. The Little Nugget (3, f). P. G. Wodehouse.

128. Ring For Jeeves (4, f). P. G. Wodehouse.

129. Trust (2, nf. Polity Press). Blog coverage here.

130. Diabetic Bone Disease: Basic and Translational Research and Clinical Applications (5, nf. Springer). Blog coverage here.

131. Very Good, Jeeves! (4, f). P. G. Wodehouse.

132. Eating disorders and the skin (3, nf. Springer). Goodreads review here. Blog coverage here and here.

133. Dead Man’s Folly (4, f). Agatha Christie.

134. Bergen-Belsen 1945: A Medical Student’s Journal (3, nf. Imperial College Press). Goodreads review here.

135. After the Funeral (4, f). Agatha Christie. Goodreads review here.

136. Crooked House (3, f). Agatha Christie. Goodreads review here.

137. Uncle Dynamite (4, f). P. G. Wodehouse.

138. The Man in the Brown Suit (2, f). Agatha Christie. Short goodreads review here.

139. Prioritization in Medicine: An International Dialogue (2, nf. Springer). Blog coverage here.

140. Endless Night (1, f). Agatha Christie. ‘A clever plot, but an unpleasant book to read’, as I put it in my goodreads review.

141. Cat Among the Pigeons (3, f). Agatha Christie. Goodreads review here.

142. Physically Speaking: A Dictionary of Quotations on Physics and Astronomy (2, nf. Taylor & Francis Group). Goodreads review here. Blog coverage here.

143. Sparkling Cyanide (4, f). Agatha Christie.

144. Disease and Medicine in World History (1, nf. Routhledge). Goodreads review here.

145. Parker Pyne Investigates (2, f). Agatha Christie. Goodreads review here.

146. Why Didn’t They Ask Evans? (2, f). Agatha Christie.

147. Fundamentals of Evidence Based Medicine (2, nf. Springer). Short goodreads review here.

148. Murder is Easy (4, f). Agatha Christie. Short goodreads review here.

149. The Seven Dials Mystery (3, f). Agatha Christie.

150. Giant’s bread (4, f). Mary Westmacott. Goodreads review here.

151. Case Study Research Methods (1, nf. Bloomsbury Academic). Goodreads review here.

152. History of Life (5, nf. Wiley-Blackwell). “In short, this is a wonderful book about the history of life on Earth, and I highly recommend it” – a quote from my goodreads review of the book. I added this book to my list of favorite books on goodreads.

153. Mrs. McGinty’s Dead (4, f). Agatha Christie.

Below I have added a short list of books I did not finish this year:

The Geometry of Special Relativity (nf. AK Peters).

Seas and Waterways of the World, Volume 1 & 2: An Encyclopedia of History, Uses, and Issues (1, nf. ABC-CLIO). Goodreads review here.

Fundamentals of Geophysical Fluid Dynamics (nf. Cambridge University Press). Not a bad book, but back when I was reading it I ended up concluding that it was simply too demanding to be worth finishing – it’s very math-heavy.

Learn from the Legends: Chess Champions at Their Best (nf. Quality Chess). I didn’t particularly like Marin’s writing style as I think the book has way too much fluff and too many irrelevant details/anecdotes, and the book was not engaging enough to motivate me to analyze the included games and positions in the amount of depth required to get much out of a book like this one. A somewhat disappointing read, which was why I did not finish it.

The Science of Reading: A Handbook (nf. Wiley-Blackwell). I found this book much too boring to be worth my time, and after approximately 100 pages I’d had enough. I might decide later on to have another go at it, but I don’t think it’s very likely that I’ll read this book from cover to cover the way I intended to when I started out reading it. The Eysenck and Keane text cover some of the same topics covered in the first part of this book, and I liked their coverage better although they go into much less detail (one to me not implausible inference being that I simply don’t care enough about the topics covered in this book to read about them in the amount of depth/detail they’re covered in this textbook).

Transdisciplinary Public Health: Research, Education, and Practice (1, nf. Jossey-Bass Education). Goodreads review here.

Couple Resilience: Emerging Perspectives (1, nf. Springer). Goodreads review here. Blog coverage here.

A Handbook of Statistical Analyses using SAS (CRC Press).

100 Endgames You Must Know (New in Chess).

Explaining Behavior: Reasons in a World of Causes (Bradford Book).

January 1, 2016 Posted by | books | Leave a comment