Department of Psychiatry, Addenbrookes Hospital, University of Cambridge, Box 189, Cambridge, CB2 0QQ, UK.
Qual Life Res. 2013 Jun;22(5):1055-63. doi: 10.1007/s11136-012-0222-7. Epub 2012 Jun 17.
To evaluate the psychometric properties of the EQ-5D and the usefulness of this instrument in psychiatric practice as a measure of health-related quality of life (HRQoL) in a sample of young adults with first-episode psychosis.
The validity of individual questionnaire items is studied using an Item Response/Latent Trait Theory modeling approach. Sensitivity of response patterns on EQ-5D items to particular diagnostic subtypes of psychosis is investigated using a finite mixture modeling approach through latent class analysis. Finally, a structural equation modeling framework is used to study differential item functioning via a multigroup approach.
Results suggest that the data closely correspond to the Rasch Rating Scale Model, and therefore that EQ-5D latent scores are equal interval measures. Despite comprising relatively few items, the instrument yields reliable measures of HRQoL for group comparisons and cost-effectiveness evaluation, but EQ-5D score is too imprecise for the assessment of HRQoL for clinical purposes at the individual level. A significant relationship was found between EQ-5D responses and type of psychosis due to inclusion of item anxiety/depression in EQ-5D. Two items (anxiety/depression, functioning in usual activities) showed an ethnicity bias.
Psychometric evidence confirmed the EQ-5D to be a valid, interval measure that is scalable according to Rasch principles.
评估 EQ-5D 的心理测量特性，以及在精神病学实践中作为评估初发精神病患者健康相关生活质量（HRQoL）的工具的实用性。
采用项目反应/潜在特质理论建模方法研究个别问卷条目的有效性。采用潜在类别分析的有限混合建模方法，研究 EQ-5D 条目的反应模式对特定精神病诊断亚型的敏感性。最后，使用结构方程建模框架通过多组方法研究差异项目功能。
结果表明，数据与 RASCH 评分量表模型密切对应，因此 EQ-5D 潜在分数是等距度量。尽管包含的项目相对较少，但该工具可用于群体比较和成本效益评估可靠地测量 HRQoL，但 EQ-5D 得分对于临床目的的个体 HRQoL 评估来说过于不精确。由于 EQ-5D 包含焦虑/抑郁项目，因此发现 EQ-5D 反应与精神病类型之间存在显著关系。两个项目（焦虑/抑郁，日常活动功能）表现出种族偏见。
心理测量学证据证实 EQ-5D 是一种有效的、区间测量工具，可根据 RASCH 原则进行缩放。
