Association between influenza infection and cardiovascular diseases: A systematic review and meta-analysis

Objectives Influenza infection may increase the risk of cardiovascular diseases (CVDs), but the extent of this link is uncertain. This systematic review and meta-analysis aimed to quantify the association between influenza infection and CVDs. Methods We conducted a comprehensive search of major databases from inception to 2024, identifying studies that investigated the association between influenza infection and CVDs. Eligible studies included cohort, case–control, and randomized controlled trials reporting on cardiovascular outcomes (acute CVDs) following influenza infection or risk of influenza infection in CVD patients (chronic CVDs). Data were extracted and pooled using random-effects models, and heterogeneity was assessed using the I 2 statistic. Results A total of 11 studies (15 datasets) involving 7327 participants were included in the meta-analysis. Overall, influenza infection was significantly associated with CVDs based on 10 datasets (odds ratio (OR) = 1.76, 95% confidence interval (CI): 1.02–3.03). However, the analysis of the five datasets indicated no significant association between pre-existing CVDs and an increased risk of influenza infection (OR = 0.91, 95% CI: 0.80–1.03). Subgroup analyses and meta-regression highlighted that study quality and design could significantly influence the risk of developing CVDs among patients with influenza. Conclusions This meta-analysis provides quantitative evidence that influenza infection could be a potential risk factor for subsequent cardiovascular events. These findings emphasize the need for preventive measures, including vaccination, especially in high-risk populations. Further research is needed to explore the underlying mechanisms and impact of influenza on cardiovascular outcomes.