Validation of diagnosis of acute myocardial infarction and stroke in electronic medical records: a primary care cross-sectional study in Madrid, Spain (the e-MADVEVA Study)

OBJECTIVES: To validate the diagnoses of acute myocardial infarction (AMI) and stroke recorded in electronic medical records (EMR) and to estimate the population prevalence of both diseases in people aged ≥18 years. DESIGN: Cross-sectional validation study. SETTING: 45 primary care centres. PARTICIPANTS: Simple random sampling of diagnoses of AMI and stroke (International Classification of Primary Care-2 codes K75 and K90, respectively) registered by 55 physicians and random age-matched and sex-matched sampling of the records that included in primary care EMRs in Madrid (Spain). PRIMARY AND SECONDARY OUTCOME MEASURES: Sensitivity, specificity, positive and negative predictive values and overall agreement were calculated using the kappa statistic. Applied gold standards were ECGs, brain imaging studies, hospital discharge reports, cardiology reports and neurology reports. In the case of AMI, the ESC/ACCF/AHA/WHF Expert Consensus Document was also used. Secondary outcomes were the estimated prevalence of both diseases considering the sensitivity and specificity obtained (true prevalence). RESULTS: The sensitivity of a diagnosis of AMI was 98.11% (95% CI, 96.29 to 99.03), and the specificity was 97.42% (95% CI, 95.44 to 98.55). The sensitivity of a diagnosis of stroke was 97.56% (95% CI, 95.56 to 98.68), and the specificity was 94.51% (95% CI, 91.96 to 96.28). No differences in the results were found after stratification by age and sex (both diseases). The prevalence of AMI and stroke was 1.38% and 1.27%, respectively. CONCLUSION: The validation results show that diagnoses of AMI and stroke in primary care EMRs constitute a helpful tool in epidemiological studies. The prevalence of AMI and stroke was lower than 2% in the population aged over 18 years.