Effectiveness of angiotensin converting enzyme inhibitors in preventing pneumonia: A systematic review and meta-analysis.

We performed a systematic review and meta-analysis to re-evaluate the effectiveness of angiotensin-converting enzyme inhibitors (ACE-I) in the reduction of pneumonia risk. We searched relevant publications in five databases. All studies included patients older than 18 years, who had used ACE-I as an intervention, and had assessed pneumonia. Seven RCTs ( n  = 8704) and 38 observational studies ( n  = 1,705,030) were included. The overall risk of bias was high. ACE-I-treated patients were associated with a slightly lower risk of pneumonia, both from pooled estimates of RCTs [pooled odds ratio (OR), 0.75; 95% confidence interval (CI), 0.62-0.90; low certainty of evidence] and observational studies (pooled OR, 0.85; 95% CI, 0.78-0.92; very low certainty of evidence). Considering the small effect size of ACE-I in preventing pneumonia and the low quality of the evidence, routine use of ACE-I for pneumonia prevention is not recommended.