[Effect of metformin on the incidence of venous thromboembolism in medical inpatients during hospitalization].

Objective: To investigate the effect of metformin on the incidence of venous thromboembolism (VTE) during hospitalization in medical inpatients. Methods: Data of 238 342 patients hospitalized in the Department of Internal Medicine of Hunan Provincial People's Hospital from January 2020 to September 2024 were retrospectively analyzed, of which 137 902 were male and 100 440 were female; age[M (Q₁,Q₃)] was 63 (54, 72) years. Patients were divided into metformin group and control group according to whether metformin was used or not, and the incidence rates of deep vein thrombosis (DVT), pulmonary thromboembolism (PTE) and bleeding events were compared between patients in the metformin group and the control group, and multifactorial logistic regression model was used to analyze the association between the use of metformin and risk of DVT, PTE, gastrointestinal hemorrhage, and bleeding from other parts of the body. Results: The incidence rates of DVT and PTE were both lower in the metformin group than in the control group [1.27% (226/17 819) vs 2.41% (5 319/220 523) and 0.11% (20/17 819) vs 0.34% (759/220 523), respectively; both P<0.001]. The incidence rates of gastrointestinal bleeding and bleeding from other sites were also lower in the metformin group compared to the control group [0.64% (114/17 819) vs 1.58% (3 488/220 523) and 0.45% (81/17 819) vs 0.60% (1 316/220 523), respectively, both P<0.05]. After adjustment for confounding factors using a multivariable logistic regression model, the risk of DVT remained significantly lower in the metformin group than in the control group (OR=0.558, 95%CI: 0.484 to 0.644). Similarly, the risk of PTE was lower in the metformin group (OR=0.557, 95%CI: 0.350 to 0.885). The risk of gastrointestinal bleeding during hospitalization was also significantly lower in the metformin group (OR=0.496, 95%CI: 0.408 to 0.603). However, the reduction in the risk of bleeding at other sites after adjustment was not statistically significant (OR=0.818, 95%CI: 0.635 to 1.052). Conclusions: Metformin reduces the risk of VTE during hospitalization in internal medicine inpatients without increasing the risk of bleeding, is protective against VTE, and may be a potential option for VTE prophylaxis in patients at high risk of bleeding.