Angiotensin-converting enzyme inhibitor use and pneumonia risk in community-dwelling older adults: results from a population-based case-control study

Purpose To test whether angiotensin-converting enzyme (ACE) inhibitor use is associated with decreased risk of community-acquired pneumonia in older adults. Methods We analyzed data from a nested case-control study of community-dwelling, immunocompetent adults aged 65-94 within an integrated healthcare delivery system. Cases of ambulatory and hospitalized pneumonia from 2000 to 2003 were identified from International Classification of Disease, version 9, codes and validated using medical record review. Controls were matched to cases by age, sex, and calendar year. Using health plan pharmacy data, we defined current use as filling >= 2 prescriptions during the 180 days prior to the case's diagnosis date. We calculated standardized doses per day using World Health Organization defined daily doses. Multivariable conditional logistic regression estimated adjusted odds ratios (ORs) for pneumonia in relation to ACE inhibitor use, adjusting for comorbidity, functional and cognitive status, and other covariates from medical record review and pharmacy data. Results Current use of ACE inhibitors was seen in 23% (242/1039) of cases and 21% (433/2022) of controls. Lisinopril accounted for 95% of prescriptions. The OR for pneumonia comparing current use to no current use was 0.99 (95% confidence interval [CI] 0.831.19). The OR for use of more than two standardized daily doses per day was 1.39 (95% CI 0.932.06) compared to no current use. Conclusions ACE inhibitor use is not associated with reduced pneumonia risk in community-dwelling older adults. Copyright (c) 2012 John Wiley & Sons, Ltd.