Association between blood type and pulmonary thromboembolism in patients with gastric cancer: A retrospective cohort study.

ObjectiveGastric cancer is associated with an increased risk of pulmonary thromboembolism. Although the ABO blood group system is a known thrombotic risk factor, its role in gastric cancer-associated pulmonary thromboembolism remains unclear.MethodsThis retrospective study analyzed 1488 gastric cancer patients to assess the association between ABO blood type and pulmonary thromboembolism. Cox proportional hazards models were used to identify independent predictors, and Kaplan-Meier analysis was used to compare cumulative incidence.ResultsPulmonary thromboembolism incidence was highest in the AB group (5.49%), while that in non-AB groups was 1.81% (p < 0.01). Multivariate analysis confirmed AB blood type (hazard ratio: 2.42, 95% confidence interval: 1.09-5.39, p = 0.03), age >65 years (hazard ratio: 2.75, 95% confidence interval: 1.30-5.82, p = 0.01), and metastasis (hazard ratio: 4.03, 95% confidence interval: 1.69-9.62, p < 0.01) as significant independent predictors. Kaplan-Meier analysis confirmed a higher cumulative pulmonary thromboembolism incidence in the AB group (log-rank test, p < 0.01). However, the O versus non-O group showed no significant differences in Kaplan-Meier analysis (log-rank test, p = 0.35).ConclusionsAB blood type is an independent risk factor for pulmonary thromboembolism in gastric cancer patients. This finding, distinct from the traditional non-O group risk model, suggests that identifying AB blood type can improve risk stratification.