Aggressive treatment of high blood pressure (hypertension) in patients who are 80 years or older is associated with lower five-year survival rates than their counterparts with blood pressure levels at or higher than treatment target levels, researchers report.

Physicians should therefore "use caution in their approach to blood pressure-lowering in this age group," they advise in the Journal of the American Geriatric Society.

Dr. Daniel J. Oates of the Boston Medical Center and his co-workers evaluated five years of data from 10 Veterans Affairs sites and Social Security files. The study group involved 4,071 ambulatory patients 80 years or older with hypertension.

The researchers found that patients with normal or higher blood pressures were less likely to die during follow-up than those with lower blood pressures. Specifically, for each 10-point decrease in blood pressure, the researchers estimated that the mortality risk increased by about 17 percent.