The generic 15D instrument is valid and feasible for measuring health related quality of life in Parkinson's disease

OBJECTIVES: To test the validity and feasibility of the generic 15D health related quality of life (HRQoL) instrument in Parkinson's disease (PD) and compare parkinsonian patients with the general population. Much effort has gone into developing disease specific HRQoL measures for PD, but only generic measures allow comparisons with the general population. New HRQoL tools are needed for PD because earlier ones have low feasibility in elderly patients. METHODS: The study comprised 260 patients with idiopathic PD and age and sex matched controls. HRQoL was evaluated using the disease specific questionnaire PDQ-39 and the 15D generic instrument. PD severity was assessed by Hoehn and Yahr staging, and the activities of daily living (ADL) and motor section of the Unified Parkinson's Disease Rating Scale (UPDRS). RESULTS: The mean 15D score (scale 0-1; overall HRQoL) was lower in PD (0.77) than in controls (0.86). Patients with PD had significantly lower scores than controls in 13 of the 15 dimensions of 15D. Scores of the corresponding dimensions of PDQ-39 and 15D correlated significantly, confirming the convergent validity of 15D. In multiple stepwise regression analysis, the UPDRS ADL score explained 55% of the variation in the 15D score. CONCLUSIONS: 15D is a valid, feasible, and sensitive tool to assess quality of life in PD. PD has a major impact on HRQoL, which is related to disease progression. Mobility, eating, speech, and sexual functions are most affected. The ADL measure of the UPDRS and the 15D provide an easily assessable view of HRQoL in PD.