Per the renewed interest in ALLHAT -- and the pros and cons of large scale, government-funded comparative effectiveness trials -- some further comment from Michael Weber, MD -- one of the original ALLHAT investigators (and Chairman of the Center for Medicine in the Public Interest):
Using ALLHAT as an example of an “evidence gap” could be misleading, for the issue is not the information produced by ALLHAT, but rather how it’s interpreted and used.
Most experts, myself included, have concluded that diuretics are highly useful drugs in treating hypertension, and may even be underutilized. But there is no convincing evidence that they are superior to other drug classes.
Admittedly, diuretics are cheap to acquire, though not necessarily cheap to use. Because they cause unwanted changes in such factors as potassium, glucose (which can lead to diabetes) and uric acid ( which can lead to gout), the additional costs of extra laboratory tests, follow-up doctor visits and corrective therapies must be reckoned in.
In fact, the British National Health Service, which is guided in drug selections by its highly cost-sensitive National Institute of Clinical Excellence, favors amlodipine (one of the diuretic’s competitors in ALLHAT) as the usual starting therapy for hypertension. This recommendation is based on the ASCOT study that found that a beta-blocker/diuretic combination (a favored treatment in ALLHAT) was significantly less effective than a combination of newer drugs in reducing fatal and non-fatal cardiovascular events and strokes.
Another powerful study, ACCOMPLISH, was recently presented at the scientific sessions of the
So the claim of an evidence gap is not based on a disregard of evidence, but in fact demonstrates that the opposite is true. Clinicians apparently are aware of the full spectrum of evidence, not just selected portions promoted by a government agency. From the perspective of patients with hypertension, this surely is good news.
(For more on ALLHAT, see here.)
