Validating abortion procedure coding in Canadian administrative databases

BACKGROUND: The British Columbia (BC) Ministry of Health collects abortion procedure data in the Medical Services Plan (MSP) physician billings database and in the hospital information Discharge Abstracts Database (DAD). Our study seeks to validate abortion procedure coding in these databases. METHODS: Two randomized controlled trials enrolled a cohort of 1031 women undergoing abortion. The researcher collected database includes both enrollment and follow up chart review data. The study cohort was linked to MSP and DAD data to identify all abortions events captured in the administrative databases. We compared clinical chart data on abortion procedures with health administrative data. We considered a match to occur if an abortion related code was found in administrative data within 30 days of the date of the same event documented in a clinical chart. RESULTS: Among 1158 abortion events performed during enrollment and follow-up period, 99.1 % were found in at least one of the administrative data sources. The sensitivities for the two databases, evaluated using a gold standard, were 97.7 % (95 % confidence interval (CI): 96.6–98.5) for the MSP database and 91.9 % (95 % CI: 90.0–93.4) for the DAD. CONCLUSIONS: Abortion events coded in the BC health administrative databases are highly accurate. Single-payer health administrative databases at the provincial level in Canada have the potential to offer valid data reflecting abortion events. TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT01174225, Current Controlled Trials ISRCTN19506752.