• Coronary disease;
  • Ethnology;
  • Prevention and Control;
  • Family characteristics

AbstractBackground: Usual ‘Yes/No’ definitions of a family history of heart disease do not allow for ‘Don't know’ responses. In some families, misclassification of family history may result if these are not considered.

Aims: To study the accuracy of family history reporting and the impact of ‘Don't know’ responses.

Methods: We compared reported family history of coronary heart disease (CHD) and cancer among 360 deceased relatives of 59 probands with ‘gold standard’ diagnoses recorded on official death certificates.

Results: For first degree relatives, sensitivity of reporting was 81% for CHD, 86% for any heart disease and 60% for cancer, while for second degree relatives, sensitivity was 73%, 69% and 90%, respectively. When ‘Don't know’ responses were classified as ‘No’, sensitivity in first degree relatives was not affected, but in second degree relatives, it fell to 49%, 41% and 60%, respectively. Specificities were unchanged. These data show that in families where information beyond first degree relatives is considered, failing to account for ‘Don't know’ responses is likely to lead to misclassification of family history of CHD. (Aust NZ J Med 1994; 24: 386–389.)