The effect of statins on the prevalence and mortality of influenza virus infection: a systematic review and meta-analysis

Introduction: Influenza virus infection is associated with high morbidity and mortality, and so additional therapeutic strategies to reduce the burden for healthcare systems are needed. Statins, by virtue of their anti-inflammato-ry and immunomodulatory effects, have been hypothesized as capable of influencing the host's response against the influenza virus. The aim of this meta-analysis was to assess the effect of ongoing statin treatment on sus-ceptibility to influenza virus infection and on influenza-associated mortality. Material and methods: Studies investigating the impact of statin treat-ment on influenza prevalence and mortality were searched for in the PubMed-Medline, Scopus, ISI Web of Knowledge, Embase, Proquest, OVID, EBSCO, and CINAHL databases (up to 8 November 2021). Fixed-and ran-dom-effects models and the generic inverse variance method were used for quantitative data synthesis.Results: In the meta-analysis of 14 arms of 2 eligible studies, including 14,997 flu-vaccinated and unvaccinated patients, treatment with statins was associated with a reduction of influenza virus prevalence (odds ratio (OR) = 0.85, 95% confidence interval (CI): 0.73-0.99; p = 0.040). No sig-nificant effect of statins on the susceptibility to influenza infection was observed in the distinct communities of either vaccinated or unvaccinated subjects. Among 9 arms of 6 eligible studies, including 87,204 patients, the use of statins among patients with influenza was associated with a reducedmortality (OR = 0.68, 95% CI: 0.56, 0.82; p < 0.001). This result was confirmed for both 30-day mortality since influenza infection diagnosis (OR = 0.61, 95% CI: 0.47, 0.80; p <0.001) and for up to 90-day mortality (OR = 0.74, 95% CI: 0.55, 1.00; p = 0.042).Conclusions: Reduced influenza prevalence and increased survival from influenza infection was observed in patients on ongoing statin treatment. Further research is needed to define the possible role of statins as adjunctive therapy in patients with influenza infection.