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.
Keywords: health related quality of life, SF-12, SF-36, coronary disease, responsiveness