Correlation between the MNCD classification-based staging of Parkinson's disease and quality of life: a cross-sectional study

Parkinson's disease (PD) is a highly heterogeneous neurodegenerative disorder with varying clinical subtypes. Recently, a novel classification called MNCD (Motor/Non-motor/Cognition/Dependency) has been proposed, which can also include staging based on disease severity. We aim to investigate which staging, the MNCD classification and staging or Hoehn and Yahr (H&Y) staging, exhibits a stronger correlation with the 39-item Parkinson's Disease Questionnaire (PDQ-39). In a cross-sectional study conducted at our single center, 357 PD patients were recruited. Data encompassed scores from various assessments such as the Movement Disorder Society of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Parts I, II, III and IV, Montreal Cognitive Assessment (MoCA), PDQ-39, and the H&Y scale. The mean age of these patients was 66.4 +/- 9.1 years old, and the majority (54.6%) were male. MNCD stages: stage 1 (N = 3, 0.8%), stage 2 (N = 62, 17.4%), stage 3 (N = 187, 52.4%), stage 4 (N = 86, 24.1%), and stage 5 (N = 19, 5.3%). The top 5 most frequent PD-related clinical symptoms were sleep disturbances (89.6%), fatigue (69.7%), mild cognitive impairment (68.9%), constipation (65.8%), and postural instability (65.5%). The PDQ-39 demonstrated a positive correlation with both MNCD staging and H&Y staging. Moreover, the MNCD staging exhibited a stronger correlation with PDQ-39 compared to H&Y staging. The correlation between the MNCD classification and staging with the quality of life in PD patients is more statistically significant compared to the H&Y staging.