Utility Assessment of Moderate to Severe Thyroid Eye Disease Health States

Abstract

Thyroid eye disease (TED) results in varying degrees of proptosis and diplopia negatively affecting quality of life (QoL), producing possibly substantial visual changes, disfigurement, and disability. To determine the association of varying TED severities with QoL in a non-TED population by assessing health state utility scores. This qualitative study, conducted from April 20, 2020, to April 29, 2021, assessed health states for active, moderate-severe TED, and values were elicited using time trade-off methods. Six health states of varying severity were determined from 2 placebo-controlled clinical trials (171 patients with TED and clinical activity score ≥4, ±diplopia/proptosis) and refined using interviews with US patients with TED (n = 6). Each health state description was validated by interviews with additional TED patient advocates (n = 3) and physician experts (n = 3). Health state descriptions and a QOL questionnaire were piloted and administered to a general population. Visual analog scales (VASs) were also administered to detect concurrence of the findings. TED health state utility scores and whether they differ from one another were assessed using Shapiro-Wilk, Kruskal-Wallis, pairwise Wilcoxon rank sum, and paired t tests. A total of 111 participants completed time trade-off interviews. The mean (SD) utility value was 0.44 (0.34). The lowest (worse) mean utility value was observed in the most severe disease state (constant diplopia/large proptosis) with 0.30 (95% CI, 0.24-0.36), followed by constant diplopia/small proptosis (0.34; 95% CI, 0.29-0.40), intermittent or inconstant diplopia/large proptosis (0.43; 95% CI, 0.36-0.49), no diplopia/large proptosis (0.46; 95% CI, 0.40-0.52), and intermittent or inconstant diplopia/small proptosis (0.52; 95% CI, 0.45-0.58). The highest (best) mean value, 0.60 (95% CI, 0.54-0.67), was observed for the least severe disease state (no diplopia/small proptosis). These findings suggest that patients with active, moderate-severe TED may have substantial disutility, with increasing severity of proptosis/diplopia more likely to have detrimental associations with QoL. These health state scores may provide a baseline for determining QoL improvement in these TED health states (utility gains) treated with new therapies.