Abstract
OBJECTIVE: To test the feasibility and validity of the EQ-5D (a widely used generic (disease non-specific) quality of life (QoL) instrument which allows comparisons between different patient groups and the general population) to assess QoL in patients with Parkinson's disease. METHODS: All 124 patients with Parkinson's disease seen in a community based study on the prevalence of parkinsonism were asked to complete a QoL battery comprising the EQ-5D, the medical outcome study short form (SF-36), the PDQ-39, a disease specific instrument to assess QoL in PD, and the Beck depression inventory. A structured questionnaire interview and a complete neurological examination including the Hoehn and Yahr stage of illness scale, the Schwab and England disability scale, the motor section of the unified Parkinson's disease rating scale (UPDRS), and the mini mental state examination (MMSE) were performed on the same day. RESULTS: The response rate was 78% and the completion rate of the EQ-5D among responders was 96%. The EQ-5D summary index correlated strongly with the PDQ-39 (r=-0.75, p<0.0001) as well as the physical score of the SF-36 (r=0.61, p<0.0001). There was a significant correlation of the EQ-5D summary index with disease severity, as measured by the Hoehn and Yahr stage of illness, the Schwab and England disability scale, the motor section of the UPDRS, and the depression score. The EQ-5D summary index also distinguished between patients with and without depression, falls, postural instability, cognitive impairment hallucinations, and those with deterioration of health over the previous year. CONCLUSION: The EQ-5D is a feasible and valid instrument to measure QoL in Parkinson's disease and reflects the severity and complications of the disease.