Jerome Hoffman, emeritus professor of medicine at UCLA and an expert in critical appraisal of medical literature, points out that almost all benefit from treating severe hypertension comes with lowering blood pressure just a little. A determined effort to lower blood pressure further, all the way to “normal,” typically requires multiple drugs and is not only usually unsuccessful but also very likely produces more harm than good, since adverse effects of intensive treatment outweigh the minimal, marginal benefit of a little more blood pressure reduction. “Drug treatment of mild hypertension, like intensive treatment of severe hypertension, may be of great value to drug makers,” Hoffman says, “but it was almost predictable that it would provide little or no benefit for patients.”
Not everyone agrees with the Cochrane review’s conclusions. William B. White of the University of Connecticut School of Medicine and president of the American Society of Hypertension, Inc. says the analysis included too few studies and too few patients to draw any reliable conclusions. He also says the studies were too short to yield meaningful results for patients with hypertension.
White says that the number of strokes was lower in patients who were treated for mild hypertension than in those who were not, but he acknowledges that the difference was not statistically significant. That means the difference may well have been due to chance rather than any effect of treatment. But he says this is because of the low number of strokes overall, and therefore he claims it is incorrect to say that treatment doesn’t prevent strokes. Wright, of the Cochrane group, counters that there was also a nonsignificant trend toward more heart attacks among treated patients. But this also might have been due to chance, and any claim about decreasing strokes would have to be accompanied by equal acknowledgement of increasing heart attacks—neither of which may be true. Wright cautioned, “If we made decisions based on [data like that], we'd make more mistakes than we already make.”
Hoffman, of UCLA, says that it is always possible to dismiss “inconveniently negative” evidence, like that in the Cochrane review, because no study can test every possible dosage or combination of medicines or duration of treatment. Thus it is always technically possible that some untested formula might work. But he calls the Cochrane review “the best evidence currently available” about the effects of drug treatment on patients with mild hypertension and says that its results fit with what is known about diminishing returns—and the potential for dangerous side effects—when treating people with less severe disease. He also objects to the idea of treating “unless and until we know for sure that it’s a bad idea,” suggesting instead that “we shouldn’t subject patients to possible harm unless and until we have reasonably good evidence that it’s worth doing.”
Given the possibility that future trials will identify at best a small, currently nonapparent benefit, it seems clear that the best thing for doctors to do would be simply to tell patients the truth—that while the best current evidence doesn’t support routine treatment of mild hypertension, we really don’t know for sure. But we do know this: Emphasizing far more effective—and evidence-based—approaches, such as exercising, quitting smoking, and following a Mediterranean diet, seems to be a very good idea. And besides, they work.