Capability versus health: a comparison of the ICECAP-O and EQ-5D-5L in elderly Chinese patients with Kashin-Beck disease

Objectives This study aimed to compare the performance of the Chinese versions of the ICECAP-O and EQ-5D-5L in patients with Kashin-Beck disease (KBD), and to explore the relationship between the two instruments. Methods Data were collected from 222 elderly Chinese patients with KBD using both the ICECAP-O and the EQ-5D-5L. To compare the two instruments and examine their relationship, we assessed floor/ceiling effects, known-groups validity (non-parametric tests with a priori hypotheses), polychoric correlations, and regression analyses. Results The Chinese version of the ICECAP-O was free of floor or ceiling effects and demonstrated known-groups validity consistent with a priori hypotheses. In contrast, the EQ-5D-5L exhibited ceiling effects in the Mobility, Self-care, Usual activities, and Anxiety/Depression dimensions, and no floor effects. The median (Q1, Q3) index scores were 0.6465 (0.5558, 0.7609) for the ICECAP-O and 0.6050 (0.3755, 0.7690) for the EQ-5D-5L. A moderate-to-strong positive polychoric correlation was found between the two instrument scores ( ρ = 0.656, p < 0.001). Regression analysis showed that both instrument scores differed across subgroups defined by sociodemographic characteristics and clinical conditions. Conclusions This study provides the first application of the ICECAP-O in patients with KBD in China. The instrument captures capability well-being dimensions beyond the EQ-5D-5L. These findings support the complementary use of both instruments for a more comprehensive assessment of patient well-being and to inform economic evaluations.