Sunday, January 26, 2014

The Inverse Benefit Law and Hypertension

I've mentioned many times the Inverse Benefit Law:
--that says that the public health effects of a drug worsen to the degree that the drug is more heavily marketed. While the Law can work via a variety of mechanisms, one common one is shifting the threshold downward at which we identify a "disease." Due to the way most biological traits are distributed in a population, the infamous bell-shaped curve, even a slight downward shift in a variable produces many more millions of "sick" people who suddenly become candidates for drug sales.

In past discussions we have often focused on cases like cholesterol and blood sugar. I've not said that much about hypertension because the data on the public health benefits of drug treatment of hypertension have seemed so unassailable--and hypertension can be treated very well with cheap generic drugs most of the time. It's therefore of interest to have a different point of view, from one of the most thoughtful commentators in British general practice, Dr. Iona Heath (subscription probably required).

Dr. Heath recounts the story of where today's hypertension guidelines came from. She recalls that the original recommendation was that we should start treating high blood pressure when the numbers exceeded 160/100. Even in that day, she argues, there were already excellent data to show that those numbers were not arbitrary--that there was good reason to believe that treating blood pressure at lower levels would produce no benefit and simply expose more patients to risks of adverse drug reactions.

Quoting one of the grand figures in British medicine, Julian Tudor Hart, Heath next describes three WHO symposia held on hypertension in the early 1980s. These were sponsored by Big Pharma and blatantly appealed to all in attendance to vote for a lower treatment threshold of 90 diastolic.

From that point on we've seen continued threshold creep as the numbers at which treatment was recommended dropped lower and lower and as we were presented with another dread disease, "pre-hypertension," that also required treatment--in every case, the guideline panels making these recommendations being awash in Pharma money. Dr. Heath illustrates how silly this has gotten by looking at a study of one county in Norway, showing that based on current European guidelines, half the population would be considered "at risk" by age 24 years and 90% by the age of 49 years. Yet Norway has just about the highest life expectancy of any nation on earth.

So now we get to the recent Cochrane review on hypertension treatment, concluding--guess what?--that one does not reduce either mortality or morbidity, according to large-scale clinical trials, if one treats hypertension at levels below 160/100, as we previously reported here:

Dr. Heath is pessimistic that practice will become truly evidence-based any time soon, as in the UK, for example, the lower thresholds have wormed their way into virtually all the crevices of the Health Service and are part of most guidelines and payment schemes.

Many people think that while it's quite dubious that we need to be treating high cholesterol in people with no existing heart disease, and high blood sugar in type 2 diabetes, at least we know that you have to be a bear about lowering blood pressure. It's sobering to be reminded that even with the poster child for disease prevention through pharmacology, things are not always as they seem, and drug money has been freely spent to be sure we don't realize that.

Hat tip to Primary Care Medical Abstracts (Drs. Rick Bukata and Jerry Hoffman) for calling this paper, from the excellent "Less is More" series in JAMA Internal Medicine, to my attention.

Heath I. Waste and harm in the treatment of hypertension. JAMA Internal Medicine 173:956-957, June 10, 2013.

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