Overall survival with warfarin vs. low‐molecular‐weight heparin in cancer‐associated thrombosis

Background When compared with warfarin, low‐molecular‐weight heparin (LMWH) reduces the incidence of recurrent venous thromboembolism (VTE) in cancer. However, a survival benefit of LMWH over warfarin for the treatment of cancer‐associated VTE has not been established. Methods Using the Surveillance, Epidemiology and End Results and Medicare linked database from 2007 through 2016, we identified Medicare beneficiaries (aged ≥66 years) who were: (1) diagnosed with primary gastric, colorectal, pancreatic, lung, ovarian, or brain cancer; (2) diagnosed with cancer‐associated VTE; and (3) prescribed LMWH or warfarin within 30 days. The primary outcome was overall survival (OS). Patients were matched 1:1 using exact matching for cancer stage and propensity score matching for cancer diagnosis, age, year of VTE, and time from cancer diagnosis to index VTE. Cox proportional‐hazards regression was performed to estimate hazard ratios (HR) and 95% confidence intervals (95% CI). Results A total of 9706 patients were included. Warfarin was associated with a significant improvement in OS compared with LMWH (median OS, 9.8 months [95% CI, 9.1–10.4] vs. 7.2 months [95% CI, 6.8–7.8]; HR, 0.86; 95% CI 0.83–0.90; p