Background The optimal therapy of venous thromboembolism (VTE) in cancer patients with renal insufficiency (RI) is unknown. Current guidelines recommend to use low-molecular-weight heparin over direct oral anticoagulants to treat VTE in cancer patients at high risk of bleeding.

Methods We used the Registro Informatizado Enfermedad Tromboemb00F3lica (RIETE) registry to compare the 6-month incidence rates of (1) VTE recurrences versus major bleeding and (2) fatal pulmonary embolism (PE) versus fatal bleeding in three subgroups (those with mild, moderate, or severe RI) of cancer patients receiving enoxaparin monotherapy.

Results From January 2009 through June 2022, 2,844 patients with RI received enoxaparin for ≥6 months: 1,432 (50%) had mild RI, 1,168 (41%) moderate RI, and 244 (8.6%) had severe RI. Overall, 68, 62, and 12%, respectively, received the recommended doses. Among patients with mild RI, the rates of VTE recurrences versus major bleeding (4.6 vs. 5.4%) and fatal PE versus fatal bleeding (1.3 vs. 1.2%) were similar. Among patients with moderate RI, VTE recurrences were half as common as major bleeding (3.1 vs. 6.3%), but fatal PE and fatal bleeding were close (1.8 vs. 1.2%). Among patients with severe RI, VTE recurrences were threefold less common than major bleeding (4.1 vs. 13%), but fatal PE was threefold more frequent than fatal bleeding (2.5 vs. 0.8%). During the first 10 days, fatal PE was fivefold more common than fatal bleeding (2.1 vs. 0.4%).

Conclusion Among cancer patients with severe RI, fatal PE was fivefold more common than fatal bleeding. The recommended doses of enoxaparin in these patients should be revisited.