How do doctors decide what is healthy and unhealthy? Do they arbitrarily decide on risk factors to line their pockets – creating false epidemics as Sandy Szwarc at Junkfood Science suggests? Or, is there actually a science, called epidemiology, that is the basis for health recommendations?
As I’ve said repeatedly, one of the sure signs you’re about to hear total BS is if someone suggests there is some conspiracy by scientists or doctors to hide the truth. In an article challenging the use of serum troponin levels to determine whether myocardial infarction (MI) has occurred (a more sensitive method) Sandy suggests this is yet another example of doctors lowering metrics of illness and risk to generate the impression of false epidemics.
There must be a health crisis to bring the greatest funding for research, treatments and education… even if an epidemic has to be created. One of the most common tactics is to change the definition. When diagnostic criteria is broadened, suddenly, with the stroke of a pen, new cases can appear to explode in number.
With heart disease deaths dropping dramatically for the past half century, the world’s top four organizations representing heart disease interests have all gotten together to change the definition … of a heart attack.
The World Heart Federation, American College of Cardiology, American Heart Association and the European Society of Cardiology have been championing the new criteria over recent years, and will officially release it next month in the Journal of the American College of Cardiology and in the AHA journal, Circulation. The new definition will use elevations of troponin levels, rather than the traditional cardiac biomarkers, such as the MB-CK enzyme.
This is a truly bizarre argument. Because measuring troponin will allow us to detect more MIs that have occurred, it must of course be part of a plot to make Americans think they’re less healthy. Never mind that more sensitive tests for MI are what is known as a good thing, and that current tests clearly are missing minor heart damage thus underestimating the number of true MIs. Any revision of current standards must be part of a plot! The fact that those scientists got together is a sure sign. We should never let them do that.
While troponins may go up for other reasons, the idea that the test will misdiagnose as heart attacks other disorders is pretty silly. This isn’t a test that is going to be used to diagnose MI in the absence of chest pain or abnormal ECG findings – which enhances the specificity of the test – and doctors are aware of confounding diagnoses – it’s their job to find them. Further, the idea that the new criteria were designed to somehow justify funding for heart disease (an area of medicine that will never lack for funding) is downright hilarious.
But this isn’t the only example of “false epidemics” being created by those greedy doctors trying to convince people that they’re ill. Sandy mentions other excellent examples.
First, because this is Sandy, is of course obesity:
“Overweight:”Definition changed from BMI â¥ 27 to BMI â¥ 25 by the U.S. National Heart Lung and Blood Institute in 1998, instantly increasing by 43% the numbers of Americans, an additional 30.5 million, deemed ‘overweight.’
So, did doctors just pull that figure out of nowhere to line their pockets? Or does data exist that justify the decision? This study in NEJM(1) is a prospective study of over a million people evaluating all-cause mortality (as well as a number of independent risk factors) showing the relationship between BMI and mortality. Here is the relevant figure – the dark line is most relevant – showing the relative risk of death versus BMI.
Continued below the fold:
The guidelines for the NHLBI cite similar (although older) studies that are the basis of their rationale. Consistent with this trial, which I think is the largest study of its kind, and studies specifically justifying the overweight recommendations (2) in a cohort of 50-70 year olds, there is a definite advantage in terms of overall mortality for keeping BMI below 25.
So, what do you think about the definition starting at 25 now? I realize BMI is an imperfect measurement, but on average it does an OK job. Until new anthropometry is developed and implemented, we should recognize that it is informative about risk within the bounds of common sense (it’s clearly off for some individuals like professional athletes and weight-lifters). I should also note that some studies have indicated a slight advantage of being overweight (25-29) in men over 55, this needs more study and may reflect the confounding tendency of the ill to lose weight before they croak.
Not satisfied with the usual obesity nonsense, she also mentions the changes in the definition of dyslipidemia:
“High cholesterol:”Definition changed from a total cholesterol â¥ 240 to â¥ 200 in 1998 increasing by 86% the numbers of Americans labeled has having high cholesterol, an additional 42.6 million adults.
Now where did we come up with that definition? Is it possible a study showed an increased risk of cardiovascular disease (CVD) with those levels? Well current standards are based on the Third Report of the National Cholesterol Education Program (NCEP) (3) also known as “ATP III”. What is their rationale for keeping the total cholesterol below 200?
Now these may seem like smaller effects, but remember, that cardiovascular deaths are such a big killer that even small decreases in risks can amount to many tens of thousands of lives being extended. It is also of note that the risk of cardiovascular events continue to decrease linearly as cholesterol drops below 200, suggesting an advantage for aggressive control especially among high-risk individuals. Statins also may have some anti-inflammatory benefit as trials lowering cholesterol using statins show benefits in excess of what one would expect from their effects on total cholesterol.
She also challenges changes in the definition of hypertension.
“Hypertension:”Definition changed in 1997 from 160/100 to 140/90, instantly adding 35% more Americans, 13.5 million, to the rosters of hypertensive. A new definition for ‘prehypertension’ in 2003 increased to 58% the Americans believing they have hypertension.
As you can see the risk increases between 70- 90mmHg diastolic (considered the more important number) and about 120-140mmHg systolic in most age groups by about 100% (note the log-linear scale though – I find this presentation annoying and a natural scale shows the importance of the 90mmHg cut-off just fine). The point of lowering the standards wasn’t to increase the number of people treated, but to include people who could benefit from treatment through lower risk of CVD. Remember again how many people die of cardiovascular disease, and cutting a risk in half through blood pressure control means many many lives saved.
Finally diabetes is apparently an engineered epidemic as well:
“Diabetes:” Definition changed from a fasting glucose of â¥ 140 to â¥ 126 in 1997 by the American Diabetes Association and WHO Expert Committee on the Diagnosis and Classification of Diabetes Mellitus, increasing by 14% and 1.7 million the people diagnosed with diabetes. With the proposal of a new term, ‘prediabetes’ by the First International Congress on Prediabetes, and promoted by the International Diabetes Federation (sponsored by 12 pharmaceutical companies), 40% of the adult population was added to the rosters believing they have diabetes and are in need of treatment.
Here we have a kernel of truth. This was an arbitrary change that doesn’t appear to show a benefit in terms of decreased morbidity or mortality. In the Expert Committee report(5) they admit their inclusion criteria were somewhat arbitrary in terms of health benefits, but did match where they felt subsequent glucose challenge testing would show a failed insulin response – a reasonable assertion.
I don’t think this means, as Sandy suggests, that they were influenced into it by the evil drug companies, but rather they didn’t properly take into consideration cost-benefit analysis of treating that extra 14% of people. As far as that and “pre-diabetes” one has to remember that diabetes is a progressive disease, and if people are showing signs of impaired glucose tolerance, it probably is wise to intervene to prevent the inevitable progression of the disease which would occur if you do nothing, and damage will accumulate as long as you have impaired glucose tolerance.
So what do you guys think? Do we have a rational for treating diseases? Or is this just more evidence of greedy doctors trying to ensure repeat visits for checking blood pressure, and diabetes and cholesterol blood work? There is a argument to be had about the cost-effectiveness of each of these interventions. These drugs do cost money, and while we may obtain a modest decrease in mortality, we may also strain the finances of the medical system as a whole. However, for Sandy to start talking about cost effectiveness doesn’t seem right considering the most cost effective interventions are diet and exercise.
1. Calle, Eugenia E., Thun, Michael J., Petrelli, Jennifer M., Rodriguez, Carmen, Heath, Clark W. Body-Mass Index and Mortality in a Prospective Cohort of U.S. Adults
N Engl J Med 1999 341: 1097-1105
2. Adams, Kenneth F., Schatzkin, Arthur, Harris, Tamara B., Kipnis, Victor, Mouw, Traci, Ballard-Barbash, Rachel, Hollenbeck, Albert, Leitzmann, Michael F. Overweight, Obesity, and Mortality in a Large Prospective Cohort of Persons 50 to 71 Years Old
N Engl J Med 2006 355: 763-778
3. National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III). NHLBI, September 2002. (http://www.nhlbi.nih.gov/guidelines/cholesterol/atp3full.pdf)
4.Age-specific relevance of usual blood pressure to vascular mortality: a meta-analysis of individual data for one million adults in 61 prospective studies, The LancetVolume 360, Issue 9349, , 14 December 2002, Pages 1903-1913.
5. Report of the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus
Diabetes Care 26: 5S-20S.