Anticoagulation in hospitalized patients with renal insufficiency: a comparison of bleeding rates with unfractionated heparin vs enoxaparin.

OBJECTIVES To compare the rates of bleeding complications in patients with renal insufficiency who receive anticoagulation therapy with the full therapeutic dose, unfractionated heparin (UFH), or with twice-daily enoxaparin. SETTING A 325-bed community teaching hospital. STUDY TYPE Retrospective cohort study. METHODS The medical records of all patients with renal insufficiency who received anticoagulation therapy with UFH or enoxaparin during a 13-month period were reviewed for the occurrence of major and minor bleeding. Incidence rates were computed per 1,000-person days of anticoagulation therapy. Comparisons were made across categories of renal insufficiency and other potential confounders. RESULTS A total of 620 patients with estimated glomerular filtration rates of < 60 mL/min were studied. Of these, 331 received anticoagulation therapy with UFH, 250 with enoxaparin, and 39 with both (not simultaneously). The major bleeding rates were 26.3 per 1,000 person-days for UFH and 20.7 per 1,000 person-days for enoxaparin. Major bleeding complications were similarly increased for both UFH and enoxaparin therapy across categories of worsening renal insufficiency. Patients with severe renal insufficiency while receiving enoxaparin had a 154% excess incidence of minor bleeding compared to those receiving UFH (incidence ratio, 2.54; 95% confidence interval, 1.01 to 6.36). Worsening renal insufficiency, female gender, and prolonged duration of anticoagulation therapy emerged as the main determinants for bleeding complications. CONCLUSION Both the twice-daily enoxaparin and UFH regimens are associated with comparable increases in major bleeding complications in patients with renal dysfunction receiving full-dose anticoagulation therapy. Both agents should be used with caution in anticoagulation therapy for patients with renal insufficiency.