Venous Thromboembolism Prophylaxis in Low Body Weight Critically Ill Patients.

Objective: To compare bleeding and thromboembolic events in low body weight patients receiving reduced-dose venous thromboembolism (VTE) prophylaxis versus standard-dose VTE prophylaxis.

Design: Multicenter, retrospective, cohort study.

Setting: Five Ascension Health Hospitals.

Patients: Adult, critically ill, low body weight (≤50 kg) patients who received either reduced-dose VTE prophylaxis (n = 140) or standard-dose VTE prophylaxis (n = 279) for at least 48 h.

Intervention: Reduced-dose prophylaxis (enoxaparin 30 mg daily or heparin 5000 units every 12 h subcutaneously) or standard-dose prophylaxis (enoxaparin 40 mg daily, enoxaparin 30 mg every 12 h, or heparin 5000 units every 8 h subcutaneously).

Measurements And Main Results: A total of 419 patients were included with a mean weight of 45.1 ± 4.2 kg in the standard-dose group and 44.0 ± 5.1 kg in the reduced-dose prophylaxis group (= .02). The primary endpoint, composite bleeding, was significantly lower in patients receiving reduced-dose prophylaxis (5% vs 12.5%,  = .02). After adjusting for confounding factors, results remained consistent demonstrating reduced composite bleeding with reduced-dose prophylaxis (odds ratio: 0.36, 95% confidence interval: 0.14-0.96). Major bleeding events occurred in 3.6% of reduced-dose patients compared with 8.6% in standard-dose patients (= .056). Clinically relevant nonmajor bleeding (5.4% vs 2.9%, = .24) and VTE (2.2% vs 0%,  = .08) events were similar between groups.

Conclusions: A reduced-dose VTE prophylaxis strategy in low body weight, critically ill patients was associated with a lower risk of composite bleeding and similar rate of thromboembolism.