PB0300 - Diagnosis of Thromboembolism in Children with Cancer: Validation of Diagnostic Algorithms using Real-World Data

Background: Pediatric cancer-related thromboembolism (TE) research is limited mainly due to small-sized studies. Real-world data provide ready access to large populations. However, there are no validated algorithms for identifying TE in real-world data for children.

Aims: To evaluate among children with cancer test characteristics (sensitivity, specificity, positive and negative predictive values) of diagnostic algorithms developed from International Classification of Diseases (ICD-9-CM and ICD-10-CA) hospitalization and physician billing codes for TE from health administrative data compared to chart review diagnoses of TE.

Methods: We used data linkage between the Pediatric Oncology Group of Ontario Network Information System (POGONIS) (Ontario pediatric cancer registry) and various administrative data housed at ICES. Reference standard was chart review data from prior studies at two institutions (from 1990-2016) among children ( < 19 years) with cancer and objectively confirmed TE. Various algorithms were developed including a single reference to one of the billing codes, multiple references with varying time between codes, and combinations of various billing codes during primary cancer therapy. Test characteristics were calculated for each algorithm. Institutional ethics boards approved the study.

Results: Records of 2,056 patients (mean age 7.67 years, SD±5.50; males 1,134) diagnosed with cancer at study sites during study period were reviewed; 112 (mean age 8.48 years, SD±5.3; males 66) had objectively confirmed TE. Eight algorithms were tested using ICD-9 and ICD-10 codes for the whole cohort (Table 1) and, for early ( < 04/2002) and later (≥04/2002, solely ICD-10 codes) periods. Step 1 algorithm with anticoagulation utilization codes was the best performing algorithm. Sensitivity was higher for later period (Table 2).

Conclusion(s): An algorithm based on combination of any TE and anticoagulation utilization codes has 75% sensitivity and 85% specificity for TE diagnosis; ICD-10 only codes improve the sensitivity to 84% with specificity at 80%. This provides a valid approach for ascertaining pediatric TE in real-world data.