Correlation Between Quality of Life and Severity of Parkinson's Disease by Assessing an Optimal Cut-off Point on the Parkinson's Disease Questionnaire (PDQ-39) as Related to the Hoehn & Yahr (H&Y) Scale

This study aim to evaluate the correlation between Quality of Life (QoL) and severity of Parkinson's Disease (PD) by assessing the presence of an optimal cut-off point on the Parkinson's disease questionnaire (PDQ-39) as related to the Hoehn & Yahr (H&Y) scale in a cohort of Italian adults with PD.

A multicenter, cross-sectional study was performed in central and northern Italy. This study was conducted on a cohort of consecutive individuals at three neurologic outpatient clinics. All participants were evaluated with the PDQ-39, and the severity of PD was recorded according to the H&Y scale by a neurologist. Receiver operating characteristic (ROC) curves and coordinates of the curve, which were visually inspected, were used to find cut-off points with optimal sensitivity and specificity. These were in turn used to determine the optimal PDQ-39 cut-off score for identifying disease severity according to H&Y stages.