Sunday, April 30, 2006

Regarding My Post on the Prehypertension/Candesartan Trial

I wanted to respond to a comment I received on my post on the prehypertension study published in the New England Journal of Medicine.

Anonymous said:

while it is true that disease dismongering to further drug companies' economic interests is bad, but look at the merits of the idea. if treating people at risk of developing hypertension reduces that risk, i do not see a problem with that. potentially, it can be life saving for thousands of people, because as we know hypertension is a risk factor for heart disease and stroke. however, it will have to be a personal choice whether or not to take candersartan on the basis of this study.

Also, they did not look at 'real' outcomes such as death, heart attacks, etc, because it's just a 2year study, and in a population of young and relatively healthy people, to get a statistically significant result in those outcomes would require many more times the number of participants.
This commenter raised some important points that warrant clarification.

There is a big difference between demonstrating that a therapeutic intervention lowers the likelihood of a true disease state occurring (i.e. hypertension) and demonstrating that such therapy improves outcomes.

Any time you begin treating milder, more benign conditions such as prehypertension, the possibility of a risk-benefit mismatch increases. The risks of the treatment begin to approach (and possibly surpass) the relatively lower risk of adverse consequences arising from the condition being treated. This is why, for example, we don’t currently treat everyone with antihypertensive medications.

Unless a randomized clinical trial later shows that treating all of mankind with blood pressure pills actually improves clinical outcomes, it is unlikely that any guidelines in favor of such treatment are likely to be published.

By the way, the study reported a four year (not two year) follow-up and I suspect that outcome data will at some point be analyzed/published in the future. If efficacy is later demonstrated (and even if it isn't) then I believe this information would be noteworthy and worthy of publication in the NEJM.

I would still have preferred that a less expensive, generic drug were tested rather than a drug that costs two dollars a pill. But that isn't the way drug studies are funded now is it?

1 Comments:

Anonymous joel topf said...

A couple of issues with your rant on this study.

First regarding the creation of a "New" class of hypertension in JNC VII. JNC VII really just renamed the old class boprderline hypertension. And importantly borderline hypertension does not just indicate people with slightly higher blood pressure than the center of the bell curve but actually over the last 40 years has been well characterized in the htn literature as a group of people who respond differently to beta blockers and dopamine, a group of people with higher circulating levels of catecholamine than normal controls and matched patients with true hypertension. It is interesting population with unique physiology and physical findings. In addition, in animal studies interupting the renin angiotensin aldosterone system with ARB/ACE eliminates the progression to htn. But the important thing is that is that you only need to eliminate it for a period and then even though you stop the drug these animals do not progress. It is as if blocking the RAAS for a period of time "cures" them of this abnormality.

This is why candesartaqn was used and not a thiazide. The science does not support thiazides, it supports ACE/ARB.

Another aspect that was unclear from your posts was the fact that patients were only given the ARB for 2 years and then given no drug for two years and the determination made after those two years.

May 22, 2006 2:22 PM  

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