1992
The USDA introduces its food guide pyramid
2005
The USDA modifies its food guide pyramid to more accurately reflect knowledge in nutrition science….Continue reading “A brief history of official dietary recommendations”
Category Archives: Medical science
More reasons statin drugs are shunned
A “reader’s comment” on an opinion piece by William C. Roberts in the American Journal of Cardiology, kindly published by the editor. Roberts’ editorial focuses on the large body of evidence favoring the cholesterol hypothesis and laments what he considers the distracting effect of complementary hypotheses (eg. inflammation, “multifactorial” nature of atherosclerosis, etc.). I offer a few points regarding the difficulties of dealing with strictly risk-based diagnoses that rely on arbitrary cut-off numbers and have no defining pathological correlates. Unfortunately not free online, but I’m happy to provide reprints upon request.
Quantophrenia in medicine and elsewhere
Pitirim Sorokin had coined the term to criticize the misapplication of quantitative methods to sociology. Murray Rothbard borrowed it from Sorokin to describe—in his usual lampooning style—the age-old fascination with mathematical modeling of economic phenomena. In his Economic Thought Before Adam Smith he points back to Pythagoras to show the influence of number mysticism on the economic thought of Aristotle (who should have known better if we recall the quote from Ethics: “it is the mark of the educated man…”). The same tendency grips Bacon and Petty who developed ‘political arithmetic’ in the 17th century. Rothbard also identifies Bernoulli’s founding of ‘mathematical economics’ as leading the way to Walras’ ‘equilibrium theory,’ and so forth.
F.A. Hayek addressed the topic directly in The Counter-Revolution of Science, detailing the origin, thoughts, and influence of the “positivists” buoyed by a transcendent enthusiasm for the exact sciences. Gilles Paquet recently published a paper titled “Quantophrenia” to review the influence of this form of numerology on public policy.
Emile Durkheim, intellectual heir to Auguste Comte and the positivists, was invoked to shed light on the theories of Geoffrey Rose, our public health maître-à-penser. Continue reading “Quantophrenia in medicine and elsewhere”
Why N of 1 is enough…
Of all the problems regarding large scale clinical trials cataloged by James Penston, the most compelling is the inverse relationship between practical value and trial size. This could almost be formulated as a law:
The clinical value of a randomized controlled trial is inversely related to its size
Of course, clinical is used in the original sense, meaning at the bedside.
It is a testimony to the effect of propaganda promoting “powerful” clinical trials that this law may sound counter-intuitive when in fact it is so obvious: if it takes 18,000 patients to demonstrate an effect, how relevant or useful is the information likely to be for a clinician dealing with an individual patient? And there is now some empirical evidence that the phenomenon of conducting, reporting, and inflating trials with “tiny effects” is getting more and more common.Continue reading “Why N of 1 is enough…”
The clinical trial on trial
It is the mark of an educated man to look for precision in each class of things just so far as the nature of the subject admits.
Aristotle
UK gastroenterologist and fellow contrarian James Penston has published two books critical of mainstream clinical research methodology. The most recent one, called Stats.con, deals with the misuse of statistics in medicine and expands on the topic of his first book published in 2003 under the title Fiction and Fantasy in Medical Research: The Large-Scale Randomised Trial.Continue reading “The clinical trial on trial”
Huff-puff: previously known as “diastolic” heart failure
This week’s JACC offers an excellent paper by Kitzman and co-workers on what is now called “Heart Failure with Preserved Ejection Fraction,” or HFPEF, (or huff-puff…).
The article reports on the cardiopulmonary physiology of 48 patients with “pure” huff-puff (no amyloid or hypertrophic cardiomyopathy) compared to 25 healthy controls. All were subjected to measurement of VO2 max and echocardiography, and the echo-derived cardiac output estimate was validated (to a reasonable extent) by radionuclide angiography.
The findings were surprising but confirm some earlier studies: Huff-puff does not seem to be due to an inability to expand diastolic volume (although end-diastolic volume at rest is decreased in Huff-puff compared to controls). Key pathophysiologic components seem to be 1) inability to increase heart rate with exercise (chronotropic incompetence); 2) inability to reduce end-systolic volume at peak exercise (yielding a relatively lower stroke volume, likely due to decreased contractility); 3) some peripheral phenomenon that interferes with oxygen extraction (calculated A-v O2 difference was reduced at peak exercise in huff-puff patients).
The accompanying editorial also offers a helpful review on the subject and on the evolution of the nomenclature.
A key unanswered question/speculation regards the role of calcium-channel blockers in this condition and to a lesser extent, beta-blockers. Both are currently “class IIb” therapies for huff-puff.
The Statistical Alchemy of Meta-Analyses
A recent post by Dr. Wes reminded me of the remarkable article Alvan Feinstein wrote in 1995 “Meta-Analysis: Statistical Alchemy for the 21st Century.” In a few clearly written pages, the founding father of clinical epidemiology brilliantly identifies the wishful thinking underlying meta-analysis and exposes its methodological fallacies.Continue reading “The Statistical Alchemy of Meta-Analyses”
Gotta love them data!
Drs. Marc Pfeffer and Marianne Bowler are commenting on the Supreme Court’s ruling in Matrixx vs. Siracusano, which upheld a lower court’s decision that a drug manufacturer must disclose to shareholders information regarding adverse effects, even absent any measure of statistical significance. But the authors would like to go beyond the court’s mandate. They advocate for “more open and better reporting” of any potential adverse effects (calling for drug companies to deliver any available piece of information “transparently,” e.g. directly to their desktop).Continue reading “Gotta love them data!”
Database doctors form new board
CHICAGO—June 16, 2011—The American Board of Medical Specialties (ABMS) has announced the creation of a new certifying body, the American Board of Database Medicine (ABDM). The announcement was made jointly by ABMS and the American Association of Database Doctors (AADD), the leading professional organization representing database medicine specialists.
“The last decades have witnessed an unprecedented epidemic of data,” said Dr. Numbar Kruntsher, president of AADD. “Studies are published everyday, and new data is produced before the old data is even digested. Thankfully, growing numbers of dedicated physicians have stepped forward to help manage data by harnessing the power of statistics and information technology. We are delighted this work is getting the recognition it deserves, and we are confident the certification pathway will ensure that data will continue to receive the high quality of care the public has come to expect.”Continue reading “Database doctors form new board”
Adiposopathy: is the evidence too thin?
In the June 21 issue of JACC, Dr. Harold E. Bays argues for establishing “adiposopathy” as a full-fledged disease to provide a coherent understanding of the role of fat tissue in cardiovascular disease, dispel the confusion related to the many-named “metabolic syndrome,” and resolve the obesity paradox. Does he succeed in this task? What would Virchow have to say?Continue reading “Adiposopathy: is the evidence too thin?”