Venous Thromboembolism Prophylaxis in Acute Medically Ill Patients: A Retrospective Cohort Study

Background and Aims

Venous thromboembolism (VTE) is considered as a preventable cause of death for hospitalized patients. Current guidelines recommend pharmacologic prophylaxis for medical patients considered high risk for VTE, despite failure of studies to show reduction in mortality. We aimed to assess the benefit and safety of VTE prophylaxis in acutely ill medical patients hospitalized in internal medicine wards.

Methods

Retrospective cohort study of all patients admitted to the internal medicine and acute geriatric departments, with an admission lasting more than 48 hours, during 2012-2018. Patients who received pharmacologic prophylaxis were compared to those who did not. The primary outcome was 30-day mortality. Secondary outcomes were the 90 day incidence of pulmonary embolism (PE), symptomatic deep vein thrombosis (DVT), and major bleeding. Propensity-weighted logistic multivariable analysis was performed.

Results

A total of 18890 patient-unique episodes were included in the analysis. Of them 3206 (17%) received prophylaxis. A total of 1309 (6.9%) died. 540/1309 (41.3%) of those who received VTE prophylaxis died and 769/1309 (58.7%) of those who did not receive prophylaxis died. VTE Prophylaxis was not associated with a reduction in mortality, multivariate-adjusted OR 0.99 (95% CI 0.84-1.14). One hundred and forty two patients (0.7%) developed VTE. The frequency of VTE among patients who received VTE prophylaxis was 31% (44/142) compared with 69% (98/142) in patients who did not receive prophylaxis. The frequency of VTE in patients who had a Padua score ≥4 and received VTE prophylaxis, was 1.9% (30/1573) compared with 1.6% (44/2797) in those with a Padua score ≥4 who did not receive prophylaxis. 74/142 (52.1%) of patients with VTE had a Padua score ≥4, 44/1309 (1.4%) of those who received VTE prophylaxis and 98/15864 (0.6%) of those who did not. VTE Prophylaxis was not associated with reduction in VTE in the whole cohort, multivariable-adjusted OR 1.09 (95% CI 0.52-2.29). VTE prophylaxis was associated with an increase in major bleeding (multivariable-adjusted OR 1.24, 95% CI 1.04-1.48)

Conclusion

The current practice of routinely administering VTE prophylaxis to medically ill patients considered at high risk for VTE, resulted in a high risk for bleeding a without clear clinical benefit, and should be reassessed.