Abstract TP396: Accuracy of Administrative Hospital, Emergency Department and Death Records

Abstract

Background: Hospital, emergency presentation and death databases are frequently used to research outcomes after stroke. The reliability of diagnostic coding for cardiovascular disease (CVD) in these administrative data remains uncertain. We aimed to determine the reliability of these data in Australia using an existing clinical trial cohort. Methods: Patients with stroke/TIA who participated in the Shared Team Approach between Nurses and Doctors For Improved Risk factor Management (STAND FIRM) trial (n = 563, recruited from 4 hospitals within Victoria). We used diagnostic ICD-10-AM coded data from hospital, emergency department and death databases within 2 years after stroke/TIA. Medical records for these potential CVD-related events were reviewed by two independent stroke specialists and adjudicated according to strict criteria. We then estimated sensitivity and specificity of using either primary or both primary and secondary diagnoses fields (obtained for all adjudicated records), against the events adjudicated by the specialists (gold standard). False positives were CVD-events defined by ICD-10-AM diagnostic codes that were adjudicated as not being a CVD-event. False negatives were true CVD-events that were misclassified as not being CVD-related when using ICD-10-AM codes. Results: We identified 261 events for medical review. After adjudication, 65 were classified as CVD-events (cases) and 196 were not CVD-events. Using both primary and secondary diagnoses, 55 true positives were correctly identified among the cases (sensitivity = 84.6%) and 129 true negatives among the non-cases (specificity = 65.8%). Using only primary diagnoses, 48 true positives were identified (sensitivity = 73.9%) and 171 true negatives (specificity = 87.2%). Using both primary and secondary diagnoses had an increased sensitivity, but decreased specificity (area under the Receiver Operating Characteristic curve (AUC) = 0.75; 95% CI, 0.70, 0.81) when compared with using only primary diagnoses (AUC = 0.81; 95% CI, 0.75, 0.86; p = 0.028). Conclusion: Both primary and secondary diagnoses should be used to identify true CVD-events and minimise misclassifying these in administrative databases.