QUALITY-OF-LIFE AFTER MYOCARDIAL-INFARCTION

The objective of this work was to develop and test a questionnaire to measure health-related quality of life for patients after myocardial i nfarction (MI). In a cross-sectional survey, 63 patients identified th e most frequent and important problems following acute myocardial infa rction. The Quality of Life after Myocardial Infarction (QLMI) instrum ent was developed on the basis of these most frequent and important pr oblems. The QLMI was administered, along with instruments measuring he alth utilities, social function, and emotional function, in a randomiz ed trial of rehabilitation versus conventional care. The most frequent and important problems fell into areas of symptoms, restriction, conf idence, self-esteem, and emotions, each of which is represented in the 26-item QLMI. Effect sizes of the overall QLMI in differentiating bet ween rehabilitation and control groups (0.35), and in detecting improv ement over 12 months (1.22) were comparable or larger than any other i nstrument. The Pearson's correlation coefficient between QLMI administ ered at 8 and 12 months following AMI varied between 0.75 and 0.87 for the five domains and the overall score. We found substantial correlat ions of the QLMI with other measures with moderate concordance with pr edictions about how the instrument should behave if it is a valid meas ure of health-related quality of life. The QLMI demonstrates a high de gree of reliability, and is more responsive than other questionnaires. Relations between the QLMI and other measures provide moderate to str ong evidence of its validity in discriminating between patients follow ing AMI according to their health-related quality of life, and in meas uring changes in health-related quality of life over time.