Question

Do angiotensin-converting enzyme (ACE) inhibitors and angiotensin-receptor blockers (ARBs) affect risk for pneumonia? Review scope Included studies compared ACE inhibitors or ARBs with placebo, each other, or any other active drug in patients with any baseline disease or risk factors, and had predefined outcomes. Outcomes were pneumonia (pneumonia, lower respiratory tract infection, or hospitalization due to lower respiratory tract infection) and pneumonia-related mortality (death directly related to pneumonia, or in-hospital death or death within 30 d of pneumonia onset). Data on upper respiratory tract infections were excluded. Review methods MEDLINE, Web of Science with conference proceedings, reference lists, reviews, and the US Food and Drug Administration (FDA) Web site were searched to June 2011 for randomized con-trolled trials (RCTs), cohort studies, and case–control studies. 37 studies met selection criteria: 18 RCTs (n = 74 097, mean age range 45 to 78 y, mean follow-up range 0.2 to 4.8 y), 11 cohort studies, and 8 case–control studies. 7 RCTs compared ACE inhibitors with controls, 9 compared ARBs with controls, and 2 compared ACE inhibitors with ARBs. 17 RCTs had adequate randomization, 8 had concealed allocation, 14 had blinding of outcome assessors, and 16 described withdrawals; 2 reported pneumonia as a prespecified outcome. Only results from RCTs are presented in this abstract. Main results ACE inhibitors had a lower risk for pneumonia than control treatment and did not differ from ARBs (Table); ARBs did not differ from control. ACE inhibitors and ARBs did not differ from control treatment or each other for pneumonia-related mortality (Table). Conclusion Angiotensin-converting enzyme inhibitors reduce risk for pneu-monia; the effect for angiotensin-receptor blockers is not clear