Reliability and validity of the Norwegian translation of the Seattle Angina Questionnaire following myocardial infarction.

The aim of this study was to validate the Norwegian version of the Seattle Angina Questionnaire (SAQ), a self-administered 19-item questionnaire designed to assess health-related quality of life in patients with chest pain or coronary artery disease. In 885 patients with prior myocardial infarction (MI), we abstracted clinical data from the patients' medical records. Two to three years after the MI, we mailed a self-administered questionnaire including the SAQ, the Short Form 36 (SF-36), and questions about current medication, to the 548 patients still alive. The response rate was 74%. Internal consistency reliability of the SAQ, assessed with Cronbach's alpha, ranged 0.75-0.92. Test-retest reliability, tested with an intraclass correlation coefficient, ranged 0.29-0.84. The pattern of association between similar and dissimilar scales of the SAQ and SF-36 mainly supported the construct validity of the SAQ. Four of the five SAQ scales discriminated between patients with different medication regimens as a proxy for severity of angina pectoris. We conclude that the Norwegian version of the SAQ showed acceptable reliability and cross-sectional validity following MI, with properties in line with the original US version.