Comparison of the short form (SF)-12 health status instrument with the SF-36 in patients with coronary heart disease.

OBJECTIVE To investigate whether a shorter health status instrument, the short form (SF)-12, is comparable with its longer version, the SF-36, for measuring health related quality of life of patients with coronary heart disease. DESIGN Prospective cohort study with follow up at six and 12 months. SETTING 18 cardiac rehabilitation centres in Germany. PATIENTS Patients were enrolled at admission to the rehabilitation centres after myocardial infarction, coronary artery bypass grafting, and percutaneous transluminal coronary angioplasty. ANALYSES Correlation coefficients were calculated between SF-12 and SF-36 physical component summary (PCS-12/-36) and mental component summary (MCS-12/-36) scores and the respective change scores. Responsiveness to change was determined with the standardised response mean. MAIN RESULTS 2441 patients were enrolled (78% men, mean (SD) age 60 (10) years; 22% women, 65 (10) years). Baseline PCS-12 and PCS-36 scores were highly correlated (r = 0.96, p < 0.001), as were baseline MCS-12 and MCS-36 scores (r = 0.96, p < 0.001). Similarly, change scores between baseline and 12 months were highly correlated (PCS-12/-36: r = 0.94, p < 0.001; MCS-12/-36: r = 0.95, p < 0.001). There was no difference in standardised response means between the SF-12 and SF-36 scales. CONCLUSIONS The SF-12 summary measures replicate well the SF-36 summary measures and show similar responsiveness to change. The SF-12 appears to be an efficient alternative to the SF-36 for the assessment of health related quality of life of patients with coronary heart disease.