A risk assessment model for the identification of hospitalized medical patients at risk for venous thromboembolism: the Padua Prediction Score

Summary.  Background: Prophylaxis of venous thromboembolism (VTE) in hospitalized medical patients is largely underused. We sought to assess the value of a simple risk assessment model (RAM) for the identification of patients at risk of VTE. Methods: In a prospective cohort study, 1180 consecutive patients admitted to a department of internal medicine in a 2‐year period were classified as having a high or low risk of VTE according to a predefined RAM. They were followed‐up for up to 90 days to assess the occurrence of symptomatic VTE complications. The primary study outcome was to assess the adjusted hazard ratio (HR) of VTE in high‐risk patients who had adequate in‐hospital thromboprophylaxis in comparison with those who did not, and that of VTE in the latter group in comparison with low‐risk patients. Results: Four hundred and sixty‐nine patients (39.7%) were labelled as having a high risk of thrombosis. VTE developed in four of the 186 (2.2%) who received thromboprophylaxis, and in 31 of the 283 (11.0%) who did not (HR of VTE, 0.13; 95% CI, 0.04–0.40). VTE developed also in two of the 711 (0.3%) low‐risk patients (HR of VTE in high‐risk patients without prophylaxis as compared with low‐risk patients, 32.0; 95% CI, 4.1–251.0). Bleeding occurred in three of the 186 (1.6%) high‐risk patients who had thromboprophylaxis. Conclusions: Our RAM can help discriminate between medical patients at high and low risk of VTE. The adoption of adequate thromboprophylaxis in high‐risk patients during hospitalization leads to longstanding protection against thromboembolic events with a low risk of bleeding.