What contributes to quality of life in patients with Parkinson's disease?

Objective-To identify the factors that determine quality of life (QoL) in p atients with idiopathic Parkinson's disease in a population based sample. Q uality of Life (QoL) Is increasingly recognised as a critical measure in he alth care as it incorporates the patients' own perspective of their health. Methods-All patients with Parkinson's disease seen in a population based st udy on the prevalence of parkinsonism were asked to complete a disease-spec ific QoL questionnaire (PDQ-39) and the Beck depression inventory. A struct ured questionnaire interview and a complete neurological examination, inclu ding the Hoehn and Yahr scale, the Schwab and England disability scale, the motor part of the unified Parkinson's disease rating scale (UPDRS part III ), and the mini mental state examination were performed by a neurologist on the same day. Results-The response rate was 78%. The factor most closely associated with QoL was the presence of depression, but disability, as measured by the Schw ab and England scale, postural instability, and cognitive impairment additi onally contributed to poor QoL. Although the UPDRS part III correlated sign ificantly with QoL scores, it did not contribute substantially to predictin g their variance once depression, disability, and postural instability had been taken into account. In addition, patients with akinetic rigid Parkinso n's disease had worse QoL scores than those with tremor dominant disease, m ainly due to impairment of axial features. Conclusion-Depression, disability, postural instability, and cognitive impa irment have the greatest influence on QoL in Parkinson's disease. The impro vement of these features should therefore become an important target in the treatment of the disease.