Unfractionated heparin versus enoxaparin for venous thromboembolism prophylaxis in intensive care units: a propensity score adjusted analysis

Venous thromboembolism (VTE) is a common complication in hospitalized patients. Pharmacologic prophylaxis is used in order to reduce the risk of VTE events. The main purpose of this study is to compare the prevalence of deep vein thrombosis (DVT) and pulmonary embolism (PE) in patients admitted to the intensive care unit (ICU) who received unfractionated heparin (UFH) versus enoxaparin as VTE prophylaxis. Mortality was evaluated as a secondary outcome. This was a Propensity Score Adjusted Analysis. Patients admitted to neurology, surgical, or medical ICUs and screened with venous doppler ultrasonography or computed tomography angiography for detection of VTE were included in the analysis. We identified 2228 patients in the cohort, 1836 (82.4%) patients received UFH and 392 (17.6%) patients received enoxaparin. Propensity score matching yielded a well-balanced cohort of 950 (74% UFH, 26% enoxaparin) patients. After matching, there was no difference in prevalence of DVT (RR 1.05; 95% CI 0.67–1.64, p = 0.85) and PE (RR 0.76; 95% CI, 0.44–1.30, p = 0.31). No significant differences in location and severity of DVT and PE between the two groups were detected. Hospital and intensive care unit stay was similar between the two groups. Unfractionated heparin was associated with a higher rate of mortality, (HR 2.04; 95% CI, 1.13–3.70; p = 0.019). The use of UFH as VTE prophylaxis in ICU patients was associated with a similar prevalence of DVT and PE compared with enoxaparin, and the site and degree of occlusion were similar. However, a higher mortality rate was seen in the UFH group.