Statins reduce all-cause mortality in chronic obstructive pulmonary disease: an updated systematic review and meta-analysis of observational studies

Recently, a number of observational studies have suggested that use of statins reduces mortality in patients suffering from chronic obstructive pulmonary disease (COPD). To obtain a more valid assessment, we update the meta-analysis of the effect of statins on COPD exacerbation and mortality. We searched for eligible articles using PubMed, Medline, Embase, the Cochrane Central Register of Controlled Trials, Cochrane Databases and Web of Science between January 2006 and February 2017, with no restrictions. The hazard ratio (HR) with 95% confidence interval (CI) was estimated. Publication bias was evaluated by funnel plot and Begg's test. Sensitivity analyses were also conducted. Twenty studies with a total of 303,981 patients were included. Thirteen articles provided data on all-cause mortality (165,221 participants), and the pooled hazard ratio of 0.65 (95% CI: 0.57-0.74, P < 0.001). Nine cohorts involving 155,435 patients reported data for COPD exacerbation with or without hospitalization, and they gave a HR of 0.58(95% CI: 0.48-0.72, P < 0.001). Our systematic review of exclusively observational studies showed a clear benefit of statins for patients suffering from COPD.