Comparative validation study of risk assessment models for pediatric hospital‐acquired venous thromboembolism

Background Risk assessment models (RAMs) have been developed to identify children at high risk of hospital‐acquired venous thromboembolism (HA‐VTE). None have been externally validated nor compared. Objectives The objective was to compare performance of these RAMs by externally validating them using the Children's Hospital‐Acquired Thrombosis (CHAT) Registry, ie, a multicenter database of children with radiographic‐confirmed HA‐VTE and corresponding controls. Patients/Methods Risk assessment models were included if the full logistic regression equation was available and all RAM variables were collected in the CHAT Registry. A random sample of 200 cases and 200 controls was selected. The performance of the RAMs was assessed for discrimination using area under the receiver operating characteristic curves (AUROC), and calibration using plots, slopes, and intercepts, and the Hosmer‐Lemeshow test. Results Three RAMs were included. Each had excellent discrimination with AUROC ≥ 0.85. However, calibration was generally poor, with calibration slopes significantly different from 1 (0.71, P