A report in the journal Chest suggests that moderate-dose statins may reduce the risk of COPD and influenza/pneumonia-related deaths. According to the researchers, some data on the “anti-inflammatory and immunomodulatory effects of statins suggest they may reduce mortality risks associated with an unchecked immune response to selected infections, including influenza and COPD”. The investigators examined this link by conducting a matched cohort study (n = 76,232) and two separate case-control studies (397 influenza and 207 COPD deaths) involving members of health maintenance organisations. Baseline illness risks from all causes prior to start of statin therapy were used to statistically adjust for the occurrence of outcomes after initiation of treatment for the cohort study.
For moderate-dose statin users (4mg/day or more), the cohort study found statistically significant reduced odds ratios (ORs) for influenza/pneumonia death (OR 0.60; 95% CI, 0.44–0.81) and COPD death (0.17; 0.07–0.42). Findings were confirmed with the case-control studies. Confounding factors not considered may explain some of the effects observed, the researchers add.
The researchers note that these findings are in general agreement with prior studies, although they alone are not proof that the observed associations are causal. They add that there is a lack of specific evidence that statins reduce the risks of influenza mortality, and the current study cannot assess reduced risks during periods when the influenza virus is circulating. Furthermore, it remains unclear whether statins will reduce influenza mortality risks for young people who are most likely to be severely affected by an avian influenza pandemic.
Another uncertainty is the duration of statin therapy needed to affect risk reduction. They conclude with regards to avian flu that “even if statins are not able to significantly reduce the risk of death from avian influenza, their use could significantly extend the time between disease onset and death. This additional survival time could increase the effectiveness of anti-influenza drugs, providing a longer time to reduce mortality risks. So far, anti-influenza drugs have not demonstrated an ability to significantly reduce the level of avian influenza human death. There remain, unfortunately, many uncertainties about the effectiveness of statins as an approach to preventing or delaying death from avian influenza. However, given the lack of effective alternatives, resolving these uncertainties should be a high priority.”