Health-related quality of life after myocardial infarction, does choice of method make a difference?

Objectives. The aim of this study was to compare health-related quality of life (HRQoL) scores obtained from the instrument Short Form (SF)-36 through the so-called SF-6D utilities, and those obtained from 15D, in patients with ST-elevation myocardial infarction (STEMI), and to evaluate the consequences in estimation of quality adjusted life years (QALYs). Design. This was a sub-study of the Norwegian District Treatment of STEMI, in which patients with STEMI treated with tenecteplase, were randomized to early angioplasty or standard management (n=266). HRQoL data were collected at all visits (0, 1, 3, 7 and 12 months). All patients with complete data were included (n=248). Results. The score range was 0.33-1.0 for SF-6D and 0.49-1.0 for 15D. Mean utility scores from 15D were higher and had different distribution compared to scores from SF-6D. Mean QALY for the whole group was higher using 15D than SF-6D (0.89 vs. 0.77). The incremental number of QALYs with early angioplasty compared to standard treatment was 0.005 (95% CI: -0.018 to 0.028) using SF-6D, and 0.004 (95% CI: -0.010 to 0.018) using the 15D instrument. Conclusions. Choice of instrument may influence HRQoL scores, but not necessarily the gain in QALYs.