Prior statin therapy and mortality among critically ill patients: a systemic review and meta-analysis of cohort studies

The effect of prior statin exposure in critically ill patients remains controversial and has not been established in previous cohort studies. We performed a systematic review of previous cohort studies to evaluate the association of prior statin therapy with mortality in critically ill patients and conducted a meta-analysis. The MEDLINE, EMBASE, and Cochrane CENTRAL databases, from their inception to January 7, 2020, were used for this study. Statin users were defined as patients prescribed statin regularly before intensive care unit admission or diagnosis of a specific disease, such as sepsis. The Cochran chi-square test and I statistics were used to determine heterogeneity between studies. In total, 199,985 critically ill patients from nine studies (44,582 statin users and 155,403 non-statin users) were included in the meta-analysis. According to the random effect model, the 30-day mortality of statin users was 31% lower than that of non-statin users (hazard ratio: 0.69, 95% confidence interval: 0.56 to 0.85). This association was similar in atorvastatin users and simvastatin users. However, hospital mortality in statin users was not significantly associated with that in non-statin users [odds ratios (ORs): 0.71, 95% CI: 0.42 to 1.21]. This study showed that there was a beneficial association of prior statin therapy with 30-day mortality in critically ill patients. However, there was no significant association with hospital mortality. Additional prospective cohort studies with a large sample size should be performed to confirm these findings.