Patients’ Self-Reported Disability Weights of Top-Ranking Diseases in Thailand: Do They Differ by Socio-Demographic and Illness Characteristics?

Abstract

Little is known about the impact of methodological decisions on estimating disability weights among patients with mental and physical disorders, and the effects of socio-demographic status on the estimation of these weights. A cross-sectional study was conducted in three hospitals in southern Thailand to describe the disability weights based on different valuation methods. Altogether, 150 patients with major depressive disorder, 150 with alcohol use disorder, and 150 with osteoarthritis with varying levels of severity were recruited. Using a face-to-face interview, all patients completed a visual analogue scale (VAS) and were randomly assigned to complete either the European Quality of Life-5 Dimensions (EQ-5D) or Time-trade-off (TTO) instrument to estimate their current utility score, which was consequently transformed to a disability weight. Significant differences were found between disability weights derived from the three instruments for the same disease, with the VAS providing the highest and EQ-5D the lowest weights. Patients with major depressive disorder had the highest disability weight while those with osteoarthritis had lowest by most methods. Patients’ socio-demographics do not affect how they perceive their disability or health condition. Our findings highlight the importance of carefully selecting methods of valuing disability weights, which can rely on disease specific conditions.

A systematic literature review of disability weights measurement studies: evolution of methodological choices

“…Among the studies that did not estimate disability weights using multi-attribute utility instruments, 59% (n = 22) included panels of medical or clinical experts or health professionals [8, 18, 19, 37, 38, 41, 43, 44, 46-49, 53, 54, 56, 59, 60, 62, 63, 65, 67, 68]. Nine studies obtained health state preferences from a general population panel [12-17, 20, 34, 51], whereas six studies included more than one panel of judges [42,45,50,52,58,66]. Specifically, Baltussen et al [50] obtained disability weights based on general population and health professionals' preferences and found that health professionals rated seven out of nine states of health as slightly to moderately less severe compared to lay people from the general population.…”

“…Ustün et al [66] showed significant differences in ranking of health conditions across 14 countries. Notably, Nontarak et al [58] derived patients' self-reported disability weights.…”

“…Six studies used web-based surveys to collect the data [13,14,19,53,59,60]. Other studies performed interviews [42,45,58,66]. Two studies obtained disability weights data using the Delphi method [46,48].…”

Comparative analysis of health state utility measurement methods

“…Another three valuations revealed that TTO<SG utility [137,140,143]. Vignette-based evaluation of mild, moderate & severe depression comparison resulted in the order of EQ-5D<TTO<VAS, with the three approaches presenting considerable differences [149].…”

“…Overall, six out of fourteen studies (43%) employed a vignette-based TTO task describing remitted/no, mild, moderate, and severe hypothetical states of depression[144][145][146][147][148][149]. The health state descriptions notably differed across studies; no identical vignettes were used.…”