Reduction of risk of pneumonia associated with use of angiotensin I converting enzyme inhibitors in elderly inpatients

Pneumonia is a major direct cause of death in the elderly. Although aspirat ion based on a reduced cough reflex is one of the causes of pneumonia in th e elderly, there are few studies of angiotensin-I converting enzyme inhibit ors (ACE inhibitors), which are antihypertensive drugs that induce cough, a s a factor influencing the incidence of pneumonia in institutionalized elde rly subjects. To assess the effect of ACE inhibitors and dihydropiridine calcium-channel blockers on the incidence of pneumonia, we conducted a hospital-based case- control study. Cases were 55 pneumonia patients aged greater than or equal to 65 years during a 1-year period. The controls were elderly subjects, fre quency matched to the cases by age and gender (n = 220). Data were collecte d on known risk factors and on medication for hypertension, consisting of A CE inhibitors, calcium-channel blockers, and nonantihypertensive medication . The significance of differences in risk factors was analyzed using univar iate and multivariate comparisons of cases and controls. After adjustment for potential confounding factors, the relative risk estim ates for pneumonia were 0.38 (95% confidence interval [CI], 0.15-0.97) and 1.84 (95% CI, 0.89-3.78) for ACE inhibitors and calcium-channel blockers, r espectively, relative to nonantihypertensive medication. The preventive eff ect of ACE inhibitors on pneumonia was apparent in long-acting ACE inhibito r users (0.24; 95% CI, 0.07-0.88). We conclude that ACE inhibitor use is an independent factor reducing risk o f pneumonia among elderly inpatients. (C) 1999 American Journal of Hyperten sion, Ltd.