Association between length of stay and postoperative survival in patients with lung cancer: a propensity score matching analysis based on National Cancer Database

BACKGROUND: Postoperative complications tend to result in prolonged hospitalization. The aim of this study was to investigate whether prolonged postoperative length of stay (LOS) can predict patient survival, particularly long-term survival. METHODS: All patients undergoing lung cancer surgery between 2004 and 2015 were identified in the National Cancer Database (NCDB). The highest quintile of LOS (more than 8 days) was defined as prolonged length of stay (PLOS). We performed 1:1 propensity score matching (PSM) between the groups with and without PLOS (Non-PLOS). Excluding confounding factors, postoperative LOS was used as a surrogate for postoperative complications. Kaplan-Meier and Cox proportional hazards survival analyses were performed to analyze survival. RESULTS: A total of 88,007 patients were identified. After matching, 18,585 patients were enrolled in the PLOS and Non-PLOS groups, respectively. Before and after matching, 30-day rehospitalization rate and 90-day mortality in the PLOS group were significantly higher than they were in the Non-PLOS group (P<0.001), indicating a potential worse short-term postoperative survival. After matching, the median survival of the PLOS group was significantly lower than that of the Non-PLOS group (53.2 vs. 63.5 months, P<0.0001). Multivariable analysis revealed that PLOS is independent negative predictor of overall survival [OS; hazard ratio (HR) =1.263, 95% confidence interval (CI): 1.227 to 1.301, P<0.001]. In addition, age (<70 or ≥70), gender, race, income, year of diagnosis, surgery type, pathological stage, and neoadjuvant therapy also were independent prognostic factors of postoperative survival for patients with lung cancer (all P<0.001). CONCLUSIONS: Postoperative LOS could be taken as the quantitative indicator of postoperative complications of lung cancer in NCDB. In this study, PLOS predicted worse short-term and long-term survival independent of other factors. Avoiding PLOS could be considered to benefit patient survival after lung cancer surgery.