A new study is turning decades of medical dogma on its head. A panel of independent experts reports this week that drugs used to treat mild cases of high blood pressure have not been shown to reduce heart attacks, strokes, or overall deaths.
Most of the 68 million patients in the United States with high blood pressure have mild, or Stage 1, hypertension, defined as a systolic (top number) value of 140-159 or a diastolic (bottom number) value of 90-99. The new review suggests that many patients with hypertension are overtreated—they are subjected to the possible harms of drug treatment without any benefit.
The study was conducted by the widely respected Cochrane Collaboration, which provides independent analyses of medical data. The “independent” part is important: The panelists who conducted the analysis don’t take money from drug companies.
Since many doctors and professional societies have been promoting treatment for mild hypertension for decades, the astute reader might wonder why this analysis was conducted only recently. The reasons are complex, but in a nutshell, researchers simply never addressed the question: Does treatment of mild hypertension help or harm patients? Instead, many authorities simply assumed that treatment helped, probably because treatment of more severe hypertension has been shown to be beneficial. In most clinical trials, patients with all degrees of hypertension were simply lumped together.
The Cochrane reviewers extracted data from all prior clinical trials to date that included test subjects treated for mild hypertension. They analyzed the outcomes of drug treatment (compared to no treatment or placebo) for nearly 9,000 patients with mild hypertension. James Wright, coordinating editor of the Cochrane Hypertension Group, told Slate that his group’s analysis doesn’t preclude the possibility that a larger study might find a small degree of benefit that was not apparent from the available data. But the fact that no benefit was detected in the Cochrane analysis means that any benefit is likely to be small—if present at all. And there’s always the possibility that the drugs cause a slight net harm. Some of the drugs are known to cause serious complications, including death.
A problem known as “disease creep” may explain the Cochrane findings. Disease creep occurs when patients with risk factors for a condition or milder cases are treated the same as patients with severe cases. Most patients with mild disease would do well in any case, so it’s easy for drug side effects to overwhelm any benefit.
Jay Siwek, editor of the journal American Family Physician, notes that disease creep can be seen in the recently created concept of “predisease”—such as “prehypertension” or “prediabetes.” Starting medication in people who have only a risk factor, even before they have any evidence of actual disease, can greatly increase profits by getting more people on medicines for far longer periods of time.