Abstract: Objective To explore the relationship between organ dysfunction and the severity of H1N1 infection. Methods Four databases (EMBASE, PubMed, Web of Science, and Cochrane) were searched for relevant studies pub‐lished between January 1, 2009, and December 15, 2024. Meta-analysis was conducted using Stata 15.0. Results A total of 52 studies were included in the final analysis. The results of the meta-analysis showed that patients with underlying dis‐eases, such as chronic pulmonary disease (OR=1.59, P<0.01) and chronic liver disease (OR=2.33, P<0.01), were more likely to develop severe cases. Elevated serum biomarkers such as creatinine (WMD=0.34 mg/dL, P<0.01) and creatine ki‐nase (WMD=0.21 U/L, P=0.027), as well as higher incidence rates of pneumonia (OR=6.59, P<0.01), heart failure (OR= 1.68, P<0.01), and multiple organ dysfunction syndrome (OR=13.00, P<0.01), were all associated with severe H1N1 infec‐tion. Conclusion Patients with underlying diseases are more likely to develop severe illness, and severe H1N1 infection is associated with multi-organ injury.

Key words: H1N1 virus, Multi-organ injury, Underlying diseases, Meta analysis