Background: Hospital-associated venous thromboembolism (HA-VTE) can be prevented by pharmacologic thromboprophylaxis. Thrombotic risk assessment models (RAMs) are essential tools to improve inadequately prescribed thromboprophylaxis. Among cases of HA-VTE, our study objectives are to explore the classifications of available thrombosis RAMs, the adequacy of thromboprophylaxis and risk factors for inadequate thromboprophylaxis.

Methods: We identified cases of HA-VTE occurring during medical hospitalizations within a multicenter Swiss venous thromboembolism (VTE) cohort (2009-2013). We calculated the proportion of VTE cases deemed at high risk with 4 VTE RAMs (Geneva, Simplified Geneva, Padua, and Improve) and the adequacy of administered pharmacologic thromboprophylaxis, and explored risk factors for underprescription of thromboprophylaxis in high-risk inpatients.

Results: Among 66 medical inpatients with HA-VTE, 60.6% had pulmonary embolism. The sensitivities of the Geneva, Simplified Geneva, Padua, and Improve RAMs were 86.4%, 80.3%, 72.7%, and 57.6%, respectively. The proportion of inadequate thromboprophylaxis was high, as 62.5%-71.1% of high-risk inpatients had not received it. Among the high-risk group according to the Simplified Geneva RAM, absence of immobilization was the only variable significantly associated with an inadequate use of thromboprophylaxis (odds ratio, 3.59; 95% confidence interval, 1.08-11.88).

Conclusions: We found a dramatically high proportion of inadequate medical thromboprophylaxis among inpatients who suffered from HA-VTE. This reinforces the need for global and local quality-improvement efforts to promote adequate use of thromboprophylaxis in elderly inpatients. Mobility may favor the underuse of thromboprophylaxis, and clinicians should stay alert to other thrombotic risk factors in mobile inpatients.