Background: Venous thromboembolism is a dreaded complication of hospitalised patients, with associated morbidity, mortality and increased healthcare costs. Previous studies have shown that pharmacological thromboprophylaxis, though effective, is inadequately administered in a large proportion of medical inpatients.

Study aims: Our primary aim was to evaluate the contemporary adequacy of thromboprophylaxis in medical inpatients admitted to two Swiss hospitals (a university hospital and a regional hospital). The secondary aim was to estimate the 90-day incidence of relevant thrombotic and bleeding events.

Methods: In this prospective cohort, patients were recruited at the University Hospital of Geneva and the Regional Hospital of Lugano between September 2020 and February 2021 and followed for 90 days for venous thromboembolism and bleeding events. The adequacy of thromboprophylaxis (pharmacological and/or mechanical) at 24h after hospital admission was evaluated according to the simplified Geneva risk score for hospital-associated venous thromboembolism.

Results: Among 200 participants (100 at each site, mean age of 65 years), 57.5% were deemed at high risk of venous thromboembolism at admission. Thromboprophylaxis was adequate in 59.5% (95% CI 52.3-66.4%). Among high-risk and low-risk inpatients, thromboprophylaxis was adequate in 71.3% and 43.5%, respectively, with differences between sites. At 90 days, risks of adjudicated venous thromboembolism, major bleeding and mortality were 1.5%, 1.5% and 6.0%, respectively.

Conclusion: Despite the extensive literature on thromboprophylaxis, the adequacy of thromboprophylaxis has not improved and remains insufficient among medical inpatients. Implementation and evaluation of clinical decision support systems are critically needed in this field.

Clinicaltrials.gov number: NCT05306821.