Chronic postsurgical pain increases postoperative depression risk.

Purpose: This retrospective cohort study aimed to investigate the association between chronic postsurgical pain (CPSP) and the risk of postoperative depression in patients undergoing major surgery.

Methods: Data from Taiwan's National Health Insurance Research Database were analysed for patients aged over 20 years who underwent major surgery between 2004 and 2018. CPSP was defined as the use of prescribed analgesics for over 3 months postsurgery, with a prescription exceeding 90 cumulative defined daily doses. Propensity score matching (PSM) was employed to match patients with and without CPSP. Cox regression analysis and competing risk analysis were conducted to evaluate the risk of postoperative depression in the CPSP group compared with the no CPSP group.

Results: Before PSM, 141 466 patients were included, with 37 303 (26.37%) experiencing CPSP. After PSM, 74 606 patients were matched in both groups. The incidence of depression was significantly higher in the CPSP group compared with the no CPSP group (p<0.0001). Cox regression analysis revealed a significantly elevated risk of depression in the CPSP group (adjusted HR: 1.41; 95% CI 1.35 to 1.48; p<0.0001), which persisted across various adjustment models and competing risk analysis. The cumulative depression risk increased over the follow-up period.

Conclusions: This study demonstrates a strong association between CPSP and postoperative depression risk. Addressing CPSP may offer a promising approach to reducing the incidence of postoperative depression and its socioeconomic and familial burdens. Further research is needed to elucidate underlying mechanisms and optimise preventive interventions.