Lamu Admassu N, Gamst-Klaussen Thor, Olsen Jan Abel
Department of Community Medicine, University of Tromsø, Tromsø, Norway.
Department of Community Medicine, University of Tromsø, Tromsø, Norway.
Value Health. 2017 Mar;20(3):451-457. doi: 10.1016/j.jval.2016.10.002. Epub 2016 Nov 23.
Most patient-reported outcome measures apply a simple summary score to assess health-related quality of life, whereby equal weight is normally assigned to each item. In the generic preference-based instruments, utility weighting is essential whereby health state values are estimated through preference elicitation and complex algorithms.
To examine the extent to which preference-weighted value sets differ from unweighted values in the five-level EuroQol five-dimensional questionnaire and the 15D instrument, on the basis of a comprehensive data set from six member countries of the Organisation for Economic Co-operation and Development, each with a representative healthy sample and seven disease groups (N = 7933).
Construct validities were examined. The level of agreement between preference-weighted and unweighted values was also assessed using intraclass correlation coefficient (ICC), Bland-Altman plots, and reduced major axis regression.
The performances of preference-weighted and unweighted measures were comparable with regard to convergent and known-group validities for each instrument. Although unweighted values in the five-level EuroQol five-dimensional questionnaire differ considerably from the preference-weighted values at the individual level, the discrepancy is minimal at the group level with a mean difference of 0.023. The ICC (0.96) and the Bland-Altman plot also suggest strong overall agreement. For the 15D, both the ICC (0.99) and the Bland-Altman plot revealed almost perfect agreement, with a negligible mean difference of -0.001. Results from the reduced major axis regression also showed small bias.
Overall, preference weighting has minimal effect if the unweighted values are anchored on the same scale as the preference-weighted value sets.
大多数患者报告的结局指标采用简单的汇总分数来评估健康相关生活质量，通常对每个项目赋予同等权重。在基于偏好的通用工具中，效用加权至关重要，即通过偏好诱导和复杂算法来估计健康状态值。
基于经济合作与发展组织六个成员国的综合数据集，每个国家有一个具有代表性的健康样本和七个疾病组（N = 7933），研究在五级欧洲五维健康量表（EuroQol five-dimensional questionnaire）和15D工具中，偏好加权值集与未加权值的差异程度。
检验结构效度。还使用组内相关系数（ICC）、布兰德-奥特曼图（Bland-Altman plots）和主轴缩减回归来评估偏好加权值与未加权值之间的一致性水平。
对于每种工具，偏好加权和未加权测量在收敛效度和已知组效度方面的表现相当。虽然五级欧洲五维健康量表中的未加权值在个体水平上与偏好加权值有很大差异，但在组水平上差异最小，平均差异为0.023。ICC（0.96）和布兰德-奥特曼图也表明总体一致性很强。对于15D，ICC（0.99）和布兰德-奥特曼图都显示几乎完全一致，平均差异可忽略不计，为-0.001。主轴缩减回归的结果也显示偏差较小。
总体而言，如果未加权值与偏好加权值集基于相同的量表，偏好加权的影响最小。
