Major bleeding in hemodialysis patients using unfractionated or low molecular weight heparin: a single-center study.

BACKGROUND: Successful hemodialysis (HD) requires circuit anticoagulation, with either unfractionated heparin (UFH) or low molecular weight heparin (LMWH) - it is not clear if differences in risk or benefit between these agents exist. We report our experience of major bleeding in patients on hemodialysis receiving either LMWH or UFH for anticoagulation of the dialysis circuit. We also examined any effect of anti-platelet agents or oral anticoagulants on bleeding rates. METHODS: An observational, retrospective, single-center study. Bleeding episodes are described using the International Society of Thrombosis and Hemostasis (ISTH) definition of a major bleeding event, and by extending this group to include all bleeds that led to a hospital admission (clinically significant). Incident event rates are reported per 100 at risk patient years, and event-free survival calculated using multivariate analysis by Cox-proportional hazard ratio. RESULTS: We report on 522 patients (792 years of exposure) in the UFHHD cohort and 889 patients (1,200 years of exposure) in the LMWH-HD cohort. The incidence of a major bleed was 1.33%, and 1.92% bleeds respectively. The incidences of clinically significant bleeding rates were 3.33% and 3.96% respectively. There was no significant difference in bleed free survival between UFH compared to LMWH (OR 0.904, CI 0.557 – 1.468, p = 0.684). Warfarin or anti-platelet usage did not increase the risk of bleeding when comparing patients not on any anticoagulants. CONCLUSIONS: There is no difference in bleeding rates between hemodialysis patients treated with either UFH or LMWH for anticoagulation of the extracorporeal circuit. We believe that both heparins have similar safety profiles when used for extracorporeal anticoagulation and that bleeding risk should not determine the choice of anticoagulation.