The 25% reduction in relative risk seen in patients treated to 120 vs 140 mm Hg corresponds to an absolute risk reduction of 1.6%.
Aggressive BP treatment draws more skeptics
Two editorialists in Annals of Internal Medicine urge caution in interpreting and adopting the findings of the SPRINT (Systolic Blood Pressure Intervention Trial), which last year showed a benefit for a more aggressive approach to blood pressure therapy. The trial found improved outcomes in high-risk patients treated to a target of of 120 mm Hg instead of 140 mm Hg.
Although the 25% reduction in relative risk in the primary composite outcome "sounds impressive," Eduardo Ortiz, MD, and Paul James, MD, wrote that this "corresponds to a decrease in event rates from 6.8% to 5.2% over 3.2 years, or an absolute risk reduction of 1.6%."
They estimated that treating 1,000 people for 3.2 years with more aggressive treatment would result, on average, in a beneficial effect in 16 persons, serious harm in 22, and no benefit or harm in 962. They write:
"Patients may believe that it is worthwhile to aim for lower BPs if they hear that receiving 3 drugs every day for more than 3 years might reduce their risk for cardiovascular events by 25%. However, after learning that their likelihood of absolute benefit is only 1.6%, with a greater likelihood of serious harm, their enthusiasm for more medications may diminish."
Given the low overall rate of events in SPRINT, "statistically significant differences may not necessarily correspond to differences that patients or their physicians consider clinically significant."
Ortiz and James also criticized the way the NIH promoted the study, emphasizing the benefits of aggressive therapy while ignoring its harms. This, they said, raises the specter of overtreatment.
They do concede that SPRINT should be incorporated into clinical practice, but the "process should carefully consider the overall body of evidence; potential harms, burdens, and costs of more aggressive treatment; and patient preferences."
They recommend a nuanced response to SPRINT as opposed to a "one-size-fits-all" approach. A more aggressive approach may be warranted in a 55-year-old high-risk patient without other conditions. More caution is warranted for a 79-year old patients with multiple comorbid conditions who is already taking two or three antihypertensive drugs.
SPRINT, they concluded, did not provide "convincing evidence that large segments of the population should be treated with additional drugs to a systolic BP goal less than 120 mm Hg, especially when the adverse events, costs, and burden of such treatment are considered."
Christie Ballantyne, MD, of Baylor College of Medicine, offered stronger support for SPRINT than other physicians asked to comment. He said that although he agreed that "'one size does not fit all' and that one must look at both risks and benefits," he thought the editorial did not provide a "fair and even" view of the trial.
"For example, if you are an older individual, one of the major concerns would be an increase in injurious falls. Although the authors of the commentary state that this is increased, in regards to serious adverse events, there were actually fewer injurious falls" and a similar number of emergency room visits.
"Why not let the individual who is 79 years old make the decision with real information, show the events that are avoided such as death and heart failure and show the increase in side effects which most patients would not consider as serious?" he asks.
Further, Ballantyne pointed out, the absolute reduction in risk is actually greater in older patients. "I do not understand why the authors of this paper suggest that we selectively ignore the much greater absolute benefit in the elderly and the greater relative risk reduction. How can the results of this study be used to say we should be aggressive in the young when they had the least benefit?"
Others contacted by MedPage Today, were likely to side with the editorial writers.
And Franz Messerli, MD, of Mt. Sinai, and Sripal Bangalore, MD, of NYU Langone Medical Center, said that there was no reason to rush to embrace SPRINT: "A simple but inescapable truth of medicine is that all patients are physiologically, psychologically, pathologically, culturally, and genetically different. Accordingly there never will be one best way to diagnose and treat many medical disorders, including hypertension. To lower systolic pressure of all hypertensive patients uniformly to 120 mm Hg or below clearly has to be considered absurd, regardless of the SPRINT results. As Ortiz and James eloquently state: 'Some patients and their physicians may believe that the benefit (of going to 120 mmHg) is worth the additional effort, risks, and costs of taking more medications, whereas others may not'. We can only hope that despite (or even because of) SPRINT physicians will continue to treat patients and not blood pressure numbers only."