Validation of physician billing and hospitalization data to identify patients with ischemic heart disease using data from the Electronic Medical Record Administrative data Linked Database (EMRALD).

BACKGROUND Reporting of ischemic heart disease (IHD) prevalence in Canada has been based on self-report or patients presenting to hospital. However, IHD often presents and can be managed in the outpatient setting. OBJECTIVES To determine whether the combination of hospital data and physician billings could accurately identify patients with IHD. METHODS A random sample of 969 adult patients from the Electronic Medical Record Administrative data Linked Database (EMRALD) - an electronic medical record database of primary care physicians in Ontario linked to administrative data for the province of Ontario - was used. A number of combinations of physician billing and hospital discharge abstracts were tested to determine the accuracy of using administrative data to identify IHD patients. RESULTS Two physician billings within a one-year period (with one of the billings by a specialist or a family physician in a hospital or emergency room setting) or a hospital discharge abstract gave a sensitivity of 77.0% (95% CI 68.2% to 85.9%), a specificity of 98.0% (95% CI 97.0% to 98.9%), a positive predictive value of 78.8% (95% CI 70.1% to 87.5%), a negative predictive value of 97.7% (95% CI 96.8% to 98.7%) and a kappa of 0.76 (95% CI 0.68 to 0.83). CONCLUSIONS A combination of physician billing and hospital discharge abstracts can be used to identify patients with IHD. Population prevalence of IHD can be measured using administrative data.