Objective: To evaluate whether the potential of statins to lower the risk of infections as published in observational studies is causal.
Design: Systematic review and meta-analysis of randomised placebo controlled trials.
Data sources: Medline, Embase, and the Cochrane Library.
Study selection: Randomised placebo controlled trials of statins (up to 10 March 2011) enrolling a minimum of 100 participants, with follow-up for at least one year.
Data extraction: Infection or infection related death.
Results: The first study selection yielded 632 trials. After screening of the corresponding abstracts and full text papers, 11 trials totalling 30 947 participants were included. 4655 of the participants (2368 assigned to statins and 2287 assigned to placebo) reported an infection during treatment. Meta-analysis showed no effect of statins on the risk of infections (relative risk 1.00, 95% confidence interval 0.96 to 1.05) or on infection related deaths (0.97, 0.83 to 1.13).
Conclusion: These findings do not support the hypothesis that statins reduce the risk of infections. Absence of any evidence for a beneficial effect in large placebo controlled trials reduces the likelihood of a causal effect as reported in observational studies.