Validation of self-reported family history of myocardial infarction using nationwide health care data

Self-reported family history of myocardial infarction (MI) is frequently used to assess cardiovascular risk. However, validation of self-reported family history has often been limited to small samples, and to death-certificates or self-reported medical history as reference. This study investigated the accuracy of self-reported family history of MI in a population-based cohort, using register data as reference. We included 25,302 participants from the Swedish CArdioPulmonary bioImage Study (SCAPIS) with sufficient register coverage. Self-reported family history of MI in parents and siblings was obtained from the SCAPIS questionnaire. Relatives were identified in the Swedish Multi-Generation Register and occurrences of MI were retrieved from the Swedish National Patient Register and Cause of Death Register. Cohen’s κ, sensitivity, specificity, and predictive values for self-reports were calculated using register-derived diagnoses as reference. The mean age of participants was 57.5 years. The overall agreement of self-reported and register-verified family history was moderate. Reporting family history of MI in any parent or sibling yielded a κ of 0.491, a sensitivity of 57.6% and a specificity of 89.0%. The positive and negative predictive values were 73.9 and 79.6%, respectively. The accuracy of reported maternal and paternal MI were similar, however, reports of early-onset disease showed lower overall κ. Male participants consistently reported family history less accurately than females, and participants with a university degree reported family history more accurately than those without a university education. Compared with register data, self-reported family history of MI underestimates the prevalence of, especially early-onset, MI in close relatives.