Development of a Pediatric-Specific Clinical Probability Tool for Diagnosis of Venous Thromboembolism: A Feasibility Study

BACKGROUND: Pediatric venous thromboembolism (VTE) is an increasingly common, difficult to diagnose problem. Clinical probability tools (CPT) for adults estimate VTE likelihood, but are not available for children. We hypothesized that a pediatric-specific CPT is feasible. METHODS: Radiology reports were utilized to identify children imaged for suspected VTE. Relevant signs, symptoms, and co-morbidity variables, identified from published literature, were extracted from corresponding medical records. Variables associated with pediatric VTE were incorporated into a multivariate logistic regression to create a pilot CPT which was confirmed on a separate cohort. RESULTS: 389 subjects meeting inclusion criteria were identified: 91 with VTE and 298 without. Univariate analysis revealed male gender (OR 2.96; p<0.001), asymmetric extremity (OR 1.76; p=0.033), central venous catheter utilization and/or dysfunction (OR 2.51; p<0.001), and cancer (OR 2.35; p=0.014) as VTE predictive variables. Documentation of an alternate diagnosis was inversely related to VTE (OR 0.42; p=0.004). Receiver operating characteristic analysis of the derived CPT demonstrated reasonable ability to discriminate VTE probability in the training cohort (AUC 0.73; p<0.001) and moderate discrimination in a separate validation cohort of 149 children (AUC 0.64; p=0.011). CONCLUSION: A pediatric-specific VTE CPT is feasible, would facilitate early diagnosis, and could lead to improved outcomes.