Validation of abdominal aortic aneurysm repair codes in Ontario administrative data

Purpose: To determine the positive predictive values (PPV) of Ontario administrative data codes for the identification of open (OSR) and endovascular (EVAR) repairs of elective (eAAA) and ruptured (rAAA) abdominal aortic aneurysms. Methods: We randomly identified 319 eAAA and rAAA repairs at two Toronto hospitals between April 2003 and March 2015, using administrative health data in Ontario, Canada. International Statistical Classification of Diseases and Related Health Problems 10th Revision (ICD-10) codes I71.3 and I71.4, were used to identify rAAA and eAAA patients, respectively. A blinded retrospective chart review was conducted and served as the gold standard comparator. Re-abstracted records were compared to Canadian Classification of Health Interventions (CCI) and Ontario Health Insurance Plan (OHIP) codes in the Canadian Institute for Health Information Discharge Abstract Database (CIHI-DAD) and OHIP databases. We calculated the PPV and 95% confidence intervals (95% CI) of individual and combined procedure and billing codes for elective and ruptured OSR and EVAR (eOSR, eEVAR, rOSR, and rEVAR). Results: Permutation of codes allowed identification of eOSR with 95% PPV (95% CI 88, 98), eEVAR with 96% PPV (95% CI 90, 99), rOSR with 87% PPV (95% CI 79, 93) and rEVAR with 91% PPV (95% CI 59, 100). Conclusions: Diagnostic, procedure and billing code combinations allow identification of eOSR, eEVAR, rOSR and rEVAR patients in Ontario administrative data with a high degree of certainty.