Department of Health Sciences, Lund University and Department of Neurology, Lund University Hospital, Lund, Sweden
Ther Adv Neurol Disord. 2009 Jul;2(4):205-14. doi: 10.1177/1756285609103726.
The 39-item Parkinson's Disease Questionnaire, and particularly its summary index (PDQ-39SI) is a widely used patient-reported clinical trial endpoint. A basic assumption when summing items into a total score is that they represent a common variable. We therefore assessed the unidimensionality of the PDQ-39SI using Rasch and confirmatory factor analysis. Both analyses showed model misfit. Adjustment for differential item functioning and disordered response category thresholds did not improve model fit, and residual analyses showed deviation from unidimensionality. These data indicate multidimensionality and challenge the interpretation and validity of PDQ-39SI scores. Clinicians and investigators should use and interpret the PDQ-39SI with caution.
帕金森病问卷共有 39 项，特别是其总结指标（PDQ-39SI），是一种广泛应用于临床试验终点的患者报告结果。将条目汇总为总分的基本假设是它们代表一个共同的变量。因此，我们使用 Rasch 和验证性因子分析来评估 PDQ-39SI 的单维性。这两种分析都显示出模型拟合不佳。调整项目间差异和无序反应类别阈值并不能改善模型拟合，残余分析显示出不符合单维性。这些数据表明存在多维性，对 PDQ-39SI 评分的解释和有效性提出了挑战。临床医生和研究人员在使用和解释 PDQ-39SI 时应谨慎。
