Gratama D.N.Weinberg L.Raykateeraroj N.Suh J.M.A.Zhao J.Hu E.P.Ratnasekara V.Freeman T.Liu D.S.Joosten A.Muralidharan V.Nikfarjam M.Lee D.K.Mahidol University2025-10-212025-10-212025-01-01Therapeutics and Clinical Risk Management Vol.21 (2025) , 1459-147211766336https://repository.li.mahidol.ac.th/handle/123456789/112691Purpose: We primarily evaluated the relationship between postoperative complications and long-term survival in patients undergoing major gastrointestinal surgery. Secondarily, we investigated the relationship between the severity and the number of complications and long-term survival. While postoperative complications are prevalent after major abdominal surgery and associated with increased mortality, the effect of their severity and accumulation remains insufficiently explored. Patients and Methods: 1989 adult patients undergoing major gastrointestinal surgery between July 2010 and April 2022 were retrospectively studied. Complications were classified using the Clavien-Dindo system. Kaplan-Meier analysis assessed long-term survival, Cox proportional hazards regression with time-dependent coefficients evaluated the impact of complications on mortality. Results: Median age was 64 years (IQR 53–74); 41.8% female and 63.0% of patients were diagnosed with malignancy. Elective procedures comprised 73.0% of cases. Complications occurred in 74.6% of patients. Mortality was higher in patients with complications (32.0%, 95% CI 29.7%-34.5%), compared to those without (21.7%, 95% CI 18.3–25.6%; P<0.001). Severe complications (Clavien-Dindo Grade ≥III) were associated with a 15.01-fold higher hazard of mortality within 18 months postoperatively (95% CI 6.83–33.0; P<0.001). Conclusion: Postoperative complications significantly reduce long-term survival following major gastrointestinal surgery. Both their severity and frequency are critical determinants of poorer outcomes, emphasizing the need for effective prevention strategies.Chemical EngineeringPharmacology, Toxicology and PharmaceuticsMedicineSocial SciencesArticleSCOPUS10.2147/TCRM.S5439132-s2.0-1050187883791178203X