Coadministration Of Statins Can Improve Pneumonia Outcomes: A Meta-analysis

Objective: Pneumonia has a severe threat against human health. Emerging epidemiological evidence suggests that coadministration of statins can improve the outcomes of pneumonia, but also no shortage of dissidents. Therefore, we searched the clinical trials about statins and pneumonia outcomes for a meta-analysis to make a comprehensive evaluation. At last, we explained the relationship between statins and pneumonia outcomes by the experimental and clinical evidences about statins pleiotropic mechanism.Methods: We searched electronic databases for the clinical trials on statins and pneumonia outcomes, and then extracted the research characteristics, adjusted effect estimates, 95% confidence intervals and the list of variables considered for inclusion in the multivariate analysis. Stata10.0 statistical software was used for the relevant calculations of the meta-analysis and results expression.Results: Six trials were included, which were cohort studies. The involved end points of the six trials: in-hospital mortality or admission into the intensive care unit (n=1), bacteremia (n=1), requirement of mechanical ventilation or inotropic support (n=1), development of complicated pneumonia (n=2), 30-day mortality (n=5), two researches in which also provided 90-day or 2.8-year mortality. The meta-analysis of statins and 30-day mortality of pneumonia: heterogeneity test: P = 0.051≈0.05, I2 = 57.5%≈50% were close to the intermediate value, but the meta regression analysis did not identify the potential confounders that could explain the heterogeneity between studies. The pooled effect estimate and 95% confidence interval according to fixed effect model: ES = 0.60 (95%CI 0.52-0.68), P<0.001; random effect model: ES = 0.52 (95%CI 0.40-0.68), P<0.001. The results were close, which both in favor of the conclusion that coadministration of statins could reduce the pneumonia 30-day mortality. The sensitivity analysis had proved that the results were reliable. The funnel plot method, the Egger's test and the Begg's test showed no publication bias existed. The meta-analysis of statins and complications of pneumonia: heterogeneity test: P = 0.247, I2 = 25.4%. The pooled effect estimate and 95% confidence interval according to fixed effect modle: ES =0.57 (95%CI 0.39-0.83), P = 0.003. It also in favor of the conclusion that coadministration of statins could reduce the complications of pneumonia. The other end points, such as requirement of mechanical ventilation or inotropic support, bacteremia, in-hospital mortality or admission to intensive care unit were just put in their original results and for the discussion.Conclusion: Results of the meta-analysis suggested that coadministration of statins may be associated with beneficial outcomes with pneumonia. Taking into account that the trials were cohort studies, mostly retrospective studies, and the presence of heterogeneity, randomized controlled trials are needed to confirm the benefit of statins in the future.