Influenza and COPD mortality protection as pleiotropic, dose-dependent effects of statins

Abstract

Background: Published data on antiinflammatory and immunomodulatory effects of statins suggest they may reduce mortality risks associated with an unchecked immune response to selected infections, including influenza and COPD. We assessed whether statin users had reduced mortality risks from these conditions.

Methods: We conducted a matched cohort study (n = 76,232) and two separate case-control studies (397 influenza and 207 COPD deaths) to evaluate whether statin therapy is associated with increased or decreased mortality risk and survival time using health-care encounter data for members of health maintenance organizations. For the cohort study, baseline illness risks from all causes prior to initiation of statin therapy were used to statistically adjust for the occurrence of outcomes after initiation of treatment.

Results: For moderate-dose (>/= 4 mg/d) statin users, this cohort study found statistically significant reduced odds ratios (ORs) of influenza/pneumonia death (OR, 0.60; 95% confidence interval [CI], 0.44 to 0.81) and COPD death (OR, 0.17; 95% CI, 0.07 to 0.42) and similarly reduced survival hazard ratios. Findings were confirmed with the case-control studies. Confounding factors not considered may explain some of the effects observed.

Conclusions: This study found a dramatically reduced risk of COPD death and a significantly reduced risks of influenza death among moderate-dose statin users.