Influence of Baseline Disease Severity on Rehabilitation Outcomes Following a Structured Exercise Program in Individuals With Chronic Parkinson's Disease: A Secondary Analysis.

Introduction Parkinson's disease is a progressive neurodegenerative disorder characterized by impaired mobility, balance, and functional independence. Although structured exercise-based rehabilitation is beneficial, rehabilitation responsiveness varies among individuals. Baseline disease severity may influence functional recovery; however, evidence regarding its relationship with rehabilitation outcomes remains limited. This secondary analysis investigated the influence of baseline disease severity on rehabilitation outcomes following a structured physiotherapy rehabilitation program in individuals with chronic Parkinson's disease. Methods This secondary analysis used data from a previously completed single-group pretest-posttest quasi-experimental study involving 20 individuals with chronic Parkinson's disease (10 male patients and 10 female patients; age range: 50-70 years). Baseline disease severity was classified using the Modified Hoehn and Yahr stage. Functional mobility and balance were assessed using the Timed Up and Go (TUG) test and Berg Balance Scale (BBS), respectively. Spearman's rank correlation coefficient was used to evaluate the relationship between baseline disease severity and rehabilitation-related improvements, while changes in Modified Hoehn and Yahr stage were analyzed using the Wilcoxon signed-rank test. Results A statistically significant moderate positive correlation was observed between baseline Modified Hoehn and Yahr stage and improvement in TUG performance (rs=0.53, p=0.015). A weak positive correlation was found between baseline disease severity and improvement in BBS scores (rs=0.30, p=0.207), although this was not statistically significant. The median Modified Hoehn and Yahr stage decreased significantly from 2.75 (IQR: 2.50-3.25) to 2.00 (IQR: 2.00-2.63) following rehabilitation (p<0.001). Conclusions Baseline disease severity may influence rehabilitation outcomes in individuals with chronic Parkinson's disease. Greater baseline Modified Hoehn and Yahr stage was significantly associated with greater improvements in functional mobility, whereas balance-related improvements were observed across disease stages without a significant association with baseline disease severity. These findings suggest that individuals with more advanced baseline disease severity may still achieve meaningful improvements in functional mobility and that advanced disease should not automatically preclude participation in structured rehabilitation programs. Larger prospective studies are needed to confirm these observations.