Clinical Experience With Pharmacological Venous Thromboembolism Prophylaxis in the Underweight and Critically Ill.

Background: The optimal regimen for pharmacological prophylaxis of venous thromboembolism (VTE) in underweight, critically ill patients is unknown.

Objective: To describe prescribing patterns for VTE prophylaxis in underweight (≤50 kg or body mass index ≤18.5 kg/m(2)), critically ill patients and identify the prevalence of VTE and bleeding.

Methods: This was a retrospective cohort study that included patients who received standard- or reduced-dose VTE prophylaxis for ≥48 hours.

Results: A total of 295 individuals were included in the study. The majority of underweight patients in this study (79.7%) received unfractionated heparin, 5000 units 3 times daily. No statistically significant difference in the prevalence of clinically relevant VTEs between the reduced- and standard-dose groups was observed (4.4% vs 5.6%, P = 1.00), but a higher proportion of bleeding events was identified within the standard-dose group (6.7% vs 11.2%, P = 0.4).

Conclusions: Empirical dose reductions of VTE prophylaxis are infrequently used in underweight, critically ill patients. Further studies need to be conducted that assess the safety and efficacy of reduced-dose VTE prophylactic regimens in this population to determine if acceptable efficacy can be achieved, with lower risks of bleeding.