External validation and model updating of the Cleveland Clinic Model for risk assessment of venous thromboembolism in medical inpatients.

BACKGROUND: Venous thromboembolism (VTE) is a leading cause of morbidity and mortality in medical inpatients. The Cleveland Clinic Model (CCM), a novel risk assessment model (RAM) to guide thromboprophylaxis, has never been independently validated. OBJECTIVE: To validate and update the CCM, and compare its prognostic accuracy with the Padua Prediction Score (PPS) and the International Medical Prevention Registry on Venous Thromboembolism (IMPROVE) score. METHODS: We used data from a prospective cohort of medical inpatients admitted >24 h to general internal medicine wards at 3 Swiss university hospitals (06/2020-01/2022). The outcome was objectively confirmed symptomatic VTE within 90 days. Patients were stratified into higher and low VTE-risk groups by RAM. We compared test characteristics across 3 versions of the CCM (original CCM and 2 updated versions, 1 with a derived cut-off, and 1 modified derived cut-off version with 45-day follow-up and without missing variables), the PPS, and the IMPROVE score and drew calibration plots for the original and modified derived cut-off CCM. RESULTS: Of 1352 medical inpatients, 28 (2.1%) experienced VTE within 90 days. The 90-day VTE cumulative incidence was 2.48% in higher-risk vs. 1.91% in low-risk patients (P = 0.52) according to the original CCM. Discrimination was poor across all RAMs (areas under the receiver operating characteristics curve ≤60%). In calibration plots, the original and modified derived cut-off CCMs underestimated the VTE risk. CONCLUSION: In this non-U.S., non-ICU cohort, all RAMs showed comparable but limited accuracy for predicting VTE up to 90 days. Updating the original CCM did not improve predictive performance.