Health utility and equity-related correlates among adults with rare diseases in Foshan City, China: an exploratory cross-sectional study using the EQ-5D-5L

Abstract

Rare diseases (RDs) are associated with substantial and potentially avoidable health inequities related to chronic disability, social disadvantage, and high non-medical costs. Evidence on health-related quality of life (HRQoL) among adults living with RDs in China remains scarce, particularly evidence on health utility values derived using the Chinese general-population value set for economic and equity-oriented analyses. We conducted a self-administered survey among adults with RDs residing in Foshan City, China using nonprobability snowball sampling. HRQoL was measured using the EuroQol 5-Dimension 5-Level (EQ-5D-5 L) instrument, and health utility values were derived from the Chinese EQ-5D-5 L value set. Guided by an equity-oriented conceptual framework, we explored associations between utility values and socioeconomic, psychosocial, and care-related factors using a cross-disease approach. Given the bounded EQ-5D-5 L utility scale, with 7 of 104 participants scoring 1.00, Tobit regression was used to examine factors associated with utility scores. A random forest model was used as a complementary approach to assess relative variable importance and assist in variable selection. A total of 104 valid questionnaires were included, covering 21 clinically heterogeneous RD types. The median EQ-5D-5 L utility score was 0.71 (interquartile range [IQR]: 0.47–0.83). The most frequently reported impairments were in anxiety/depression (80.8%) and pain/discomfort (78.8%). Within this sample, full caregiving dependence ( β = -0.77, 95% CI : -0.95 to -0.58), experience of discrimination ( β = -0.23, 95% CI : -0.36 to -0.10), receipt of assistance from social organizations ( β = -0.13, 95% CI : -0.24 to -0.02), and direct non-medical expenses of ≥ ¥10,000 ( β = -0.13, 95% CI : -0.24 to -0.03) were associated with lower utility ( P < 0.05). Sensitivity analyses showed broadly consistent associations for caregiving dependence, receipt of assistance from social organizations, and discrimination, whereas the association with direct non-medical expenses varied according to its operationalization and the model specification used. In this small and diagnostically heterogeneous sample from Foshan City, adults with RDs experienced reduced health utility. The factors associated with utility suggest potentially equity-relevant challenges linked to psychosocial vulnerability and economic burden beyond direct medical care. These exploratory, cross-disease findings are not disease-specific and require confirmation in larger, representative, and diagnosis-informed studies before policy implications can be established.