[Statin in the treatment of ALI/ARDS: a systematic review and Meta-analysis based on international databases]

To confirm the effects of statin therapy on mortality of patients with acute lung injury/acute respiratory distress syndrome (ALI/ARDS).

PubMed/Medline, Embase, Web of Science and Cochrane Central Register of Controlled Trials were searched for articles using the terms "acute lung injury", "ALI", "acute respiratory distress syndrome", "ARDS", "statin", "simvastatin" and "rosuvastatin" updated to November 17, 2015. Randomized controlled trial (RCT) or observational cohort studies investigating the effects of statin therapy on mortality in patients with ALI or ARDS were all identified, without date or language restriction. The control group was given conventional treatment, while the experimental group was treated with statins additionally. The primary outcome was in-hospital mortality. Meanwhile, ventilator-free day, intensive care unit (ICU)-free day, ICU length of stay (LOS) and ICU mortality were also analyzed. RevMan 5.2 and STATA 13 software were used for systematic review and Meta analysis, and funnel plot was used to analyze the publication bias.

A total of five trials including three randomized controlled trials and two observational studies were included. Among 1 636 patients enrolled in the study, there were 739 patients in experimental group, and 897 in control group. It was shown by Meta analysis that there was no significant difference in in-hospital mortality between experimental group and control group [relative risk (RR) = 0.96, 95% confidence interval (95%CI) = 0.79-1.15, P = 0.63]. The subgroup analysis based on RCT and cohort study, or the subgroup analysis of different statins showed that there was no significant difference in in-hospital mortality between the experimental group and the control group (both P > 0.05). There were no significant differences in ventilator-free days [mean difference (MD) = 1.41, 95%CI = -0.32-3.13, P = 0.11], ICU-free days (MD = -0.23, 95%CI = -1.61-1.15, P = 0.75), ICU length of stay (MD = -1.03, 95%CI = -6.55-4.50, P = 0.72), or ICU mortality (RR = 0.88, 95%CI = 0.68-1.14, P = 0.33) between the experimental group and the control group. It was shown by funnel plot that there was no publication bias in in-hospital mortality.

The systematic review and meta-analysis suggests that statin may not be associated with a significant reduction in mortality, ventilator-free day, ICU-free day and ICU length of stay in patients with ALI/ARDS.