Evaluation of a measurement strategy for Parkinson's disease: assessing patient health-related quality of life

Abstract

This study evaluated the feasibility and psychometric properties of self-completed and telephone interview versions of a patient health-related quality-of-life (HQL) questionnaire for Parkinson's disease that included the SF-36 Health Survey (SF-36), the Parkinson's Disease Questionnaire (PDQ-39), and the Medical Outcomes Study Sexual Function Survey. Parkinson's disease patients (n = 150) completed the questionnaire twice: once at the study site and once over the telephone in a randomized order. Ninety-four percent of enrolled patients completed the first HQL assessment and 88% completed both assessments. Cronbach's alpha exceeded 0.70 for all scales except for the self-completed PDQ-39 Social Support subscale (0.57) and the telephone interview PDQ-39 Social Support (0.60) and Cognitions (0.67) subscales and the SF-36 General Health (0.60) and Social Function (0.61) subscales. There were no statistically significant differences in mean HQL scale scores across the two modes of administration. Mean scores for 3 of the PDQ-39 subscales and the Summary Index were significantly poorer (p < 0.05) for patients at later clinical stages. Similarly, patients with dyskinesias reported significantly poorer scores for 4 of the PDQ-39 subscales and the Summary Index and patients with self-reported comorbidities reported poorer SF-36 Physical Function and General Health subscale scores than patients without dyskinesias and comorbidities, respectively. This study suggests that the self-completed and telephone interview versions of the patient HQL questionnaire are feasible and valid for future clinical trial applications.