Older patients with isolated systolic hypertension who were treated with chlorthalidone as part of a clinical trial in the late 1980s showed a significant gain in life expectancy 22 years later, according to a report in the Dec. 21 issue of JAMA.
"The gain in life expectancy free from cardiovascular death corresponds with approximately 1 day gained for each month of treatment," said Dr. John B. Kostis of the Cardiovascular Institute at the Robert Wood Johnson Medical School, New Brunswick, N.J., and his associates.
Getting this message out to patients and clinicians "may result in increased patient adherence to drug therapy, and decrease the degree of therapeutic inertia by health care providers," the investigators noted.
Although antihypertensive drug therapy is known to decrease cardiovascular events, there have been no long-term data on a possible gain in life expectancy. To assess such long-term outcomes, Dr. Kostis and his colleagues obtained mortality data on subjects who had participated in SHEP (Systolic Hypertension in the Elderly Program), a randomized, placebo-controlled trial that began in 1984 and concluded in 1990.
"The gain in life expectancy free from cardiovascular death corresponds with approximately 1 day gained for each month of [chlorthalidone] treatment."
In the trial, men and women aged 60 years and older (mean age, 72 years) at baseline who had isolated systolic hypertension were treated for a mean of 4.5 years with either stepped-care chlorthalidone (2,365 subjects) or placebo (2,371 subjects). At the end of the study, active drug was found to prevent one out of two admissions for heart failure, one out of three fatal or nonfatal strokes, and one out of four coronary heart disease events.
However, the effects on all-cause mortality and cardiovascular mortality were not significant at that time.
At the conclusion of the SHEP study, all the subjects were advised to continue taking active therapy.
Dr. Kostis and his associates assessed mortality in these study subjects by matching their personal identifiers to the National Death Index through the end of 2006. At that time, about 60% of both the active therapy group and the placebo group had died.
Life expectancy gain was greater for the study subjects who had received chlorthalidone than for those who had received placebo. The gain was 158 days for cardiovascular death and 105 days for all-cause mortality.
These gains were even greater in the subgroup of patients who achieved their target systolic blood pressure level while taking chlorthalidone.
For the study population as a whole, each month of antihypertensive therapy was associated with a 1-day extension of life expectancy free from cardiovascular death, the researchers said (JAMA 2011;306:2588-93).
It is important to note that newer antihypertensive agents that have been developed since the SHEP trial concluded "may be equally or more effective in decreasing cardiovascular events or may have a better adverse event profile," they noted.
This study was supported in part by the National Heart, Lung, and Blood Institute; the National Institute on Aging; and the Robert Wood Johnson Foundation. One of Dr. Kostis’s associates reported ties to Amgen and Merck; no other financial conflicts of interest were reported.