Comparison of preference-based utilities of the Short-Form 36 Health Survey and Health Utilities Index before and after treatment of patients with intermittent claudication

The authors compared SF-36 utilities with Health Utilities Index (HUI) utilities (HUI2 and HUI3) assessed in patients with intermittent claudication. A total of 87 patients with intermittent claudication completed the SF-36 and HUI before and 1, 3, and 12 months after revascularization. Utilities were estimated using SF-36 and HUI published algorithms (i.e., both algorithms were based on standard-gamble utilities assessed in random samples of the general population). The utilities were compared using repeated-measures multivariate analysis of variance, paired t tests, and univariate linear regression analyses. Before treatment, the mean SF-36 and HUI3 utilities were the some (0.66 vs. 0.66, P = 0.92) and less than the mean HUI2 utility (0.70, P = 0.02). After treatment, all utilities showed improvement from before treatment (P < 0.05); the gain in utilities from treatment was lowest when using the SF-36 (e.g., 0.74, 0.80, 0.77 at 3 months for the SF-36, HUI2, and HUI3, respectively). The correlations of changes over time of the SF-36 with HUI2 utilities and of the SF-36 with HUI3 utilities were 0.39 and 0.49, respectively. The relationships between the SF-36 and HUI2 or HUI3 utilities were moderate to good (i.e., range-adjusted R-2 = 31% to 72%). The results suggest that SF-36 data can be transformed to preference-based utilities and be used for economic evaluation in health care. The gain in utilities from treatment, however, was less for SF-36 utilities than for HUI utilities.