Health-related quality of life in patients with coronary artery disease treated for angina: validity and reliability of German translations of two specific questionnaires.

The German versions of two patient-perceived heart disease specific health-related quality of life (HRQL) questionnaires, the Seattle Angina Questionnaire (SAQ) and the MacNew Heart Disease questionnaire, were examined for their psychometric properties in patients with angiographically documented coronary artery disease and angina who were treated either medically or invasively and followed up for 1 year. Both HRQL questionnaires and the modified Canadian Cardiovascular Society (CCS) angina-associated disability scale were completed by 158 patients at baseline and 12 months later when they also completed a generic health status questionnaire, the SF-36. Both specific HRQL questionnaires were acceptable to patients. Three of the four MacNew scales, but none of the SAQ scales, discriminated between patients by baseline CCS disability levels I and IV. Internal consistency ranged from 0.75 to 0.94 for the SAQ and from 0.86 to 0.97 for the MacNew scales. Test-retest reliability over a 4-week period of time ranged from 0.45 to 0.81 for the SAQ scales and 0.61 to 0.68 for the MacNew scales. Over 12 months, HRQL improved (p < 0.001) on three of the five SAQ and on all four of the MacNew scales with the responsiveness statistic ranging from 0.59 to 1.55 for the SAQ and 0.86 to 1.12 for the MacNew. The 12 month scores on all SAQ and MacNew scales were significantly higher in patients who improved than those who deteriorated on the SF-36 reported health transition question. We conclude that the SAQ and the MacNew are both valid, reliable, and responsive in German, that the MacNew discriminates better between angina grades at baseline, that HRQL improves over 12 months with both measures, that the SAQ angina frequency and disease perception scales have the largest effect sizes, and that the 12-month change in HRQL with both instruments was associated with change in SF-36 reported health transition status.