Do angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers decrease the risk of hospitalization secondary to community-acquired pneumonia? A nested case-control study

Study Objective. As studies have shown that angiotensin-converting enzyme (ACE) inhibitors may lower the risk of developing pneumonia by increasing the cough reflex, we sought to explore the potential association between use of ACE inhibitors and the risk of hospitalization secondary to community-acquired pneumonia (CAP). To test this hypothesis further, we also looked at the risk for CAP in those taking angiotensin II receptor blockers (ARBs), as these drugs have a similar mechanism of action to that of ACE inhibitors but have minimal or no effect on the cough reflex. In addition, the putative protection against pneumonia may instead be related to general inhibition of the renin-angiotensin system. Design. Nested case-control study Data Source. Universal Quebec, Canada, administrative health databases. Patients. From a cohort of 47,148 patients with coronary artery disease who had a revascularization procedure between 1996 and 2000, 1666 patients with CAP and 33,315 time-matched control subjects (20 controls for each case) were identified. Measurements and Main Results. Conditional. logistic regression analysis was used to estimate rate ratios, while controlling for potential confounders. No association was observed between patients receiving ACE inhibitors and hospitalization for CAP (rate ratio [RR] 0.98, 95% confidence interval [CI] 0.69-1.40). A similar lack of association was noted for those receiving ARBs (RR 1.02, 95% CI 0.70-1.49). Conclusion. In this case-control study, no association was found between use of ACE inhibitors or ARBs and risk of hospitalization secondary to CAR Future studies are necessary to explore this association further.