NEW YORK (Reuters Health) Every month of treatment for hypertension leads to almost one extra day of life free from cardiovascular death, researchers report in the Journal of the American Medical Association for December 21.

“Reporting that each month of antihypertensive therapy was associated with 1 day prolongation of life expectancy free from cardiovascular death is a strong message that may result in increased patient adherence to drug therapy and decrease the degree of therapeutic inertia by health care providers,” the authors write.

The finding comes from a long-term follow-up of participants in the SHEP (Systolic Hypertension in the Elderly Program) trial, in which 4,736 patients with isolated systolic hypertension were randomized in 1985-1988 to chlorthalidone-based stepped care therapy or placebo for 4.5 years. After the trial, all the participants were advised to receive antihypertensive therapy.

By December 31, 2006, 59.9% of those in the chlorthalidone and 60.5% in the placebo group had died, Dr. John B. Kostis, at the UMDNJ-Robert Wood Johnson Medical School in New Brunswick, New Jersey, and colleagues report.

They calculated that the net gain in life expectancy free from cardiovascular death, based on the area between survival curves, was 158 days for the active treatment group compared to the placebo group. The corresponding gain in all-cause life expectancy was 105 days.

This gain in life expectancy is important, because it occurred among persons with a mean age of 72 years at baseline, the researchers comment. The gain in life expectancy free from cardiovascular death corresponds with 1 day (0.89 days) gained per month of treatment for this cohort. For all-cause mortality, the gain in life expectancy resulting from 1 month of antihypertensive drug treatment would be a half day (0.59 days), they estimate.

In a complementary measure, the team determined the difference in survival at the 70th percentile between the two groups. They found that this was 1.41 years longer in the chlorthalidone group than the placebo groups (i.e. 17.81 vs 16.39 years; p=0.01) for survival free from cardiovascular death and 0.56 years (11.53 vs 10.98 years; p=0.03) in terms of all-cause mortality.

In discussing the results, Dr. Kostis and colleagues point out that the findings apply to patients with isolated systolic hypertension who received chlorthalidone-atenolol stepped care. However, the prevalence of hypertension increases with age and the majority of older persons have this condition, they note.

Also they add, newer antihypertensive agents may be equally or more effective in decreasing cardiovascular events or may have a better adverse effect profile than the medications used in the SHEP trial.

Reference:

JAMA 2011;306:2588-2593.