Clinical and functional characteristics of Parkinson’s disease in patients with chronic kidney disease

Objective. To evaluate the clinical and functional characteristics of Parkinson’s disease in patients with and without concomitant chronic kidney disease (CKD) and to assess the impact of renal dysfunction on motor, cognitive, and non-motor symptoms. Material and methods. A cross-sectional study was conducted involving 62 patients diagnosed with idiopathic Parkinson’s disease at stages I—III. The test group comprised 31 patients with an estimated glomerular filtration rate (eGFR) of 30—59 mL/min/1.73 m², while the control group comprised 31 patients with an eGFR of 60 mL/min/1.73 m² or higher. Various assessments were performed, including the Movement Disorder Society Unified Parkinson’s Disease Rating Scale (MDS-UPDRS), Hoehn and Yahr Scale, Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), and evaluations for depression, anxiety, and orthostatic dysfunction. Results. Demographic factors such as age, sex, and duration of Parkinson’s disease were similar between the groups; however, patients with CKD had a higher Hoehn and Yahr score (2.5 vs. 2.0; p<0.05). Although the levodopa equivalent dose was greater in this cohort, the difference was not statistically significant. With an equal duration of the disease, motor impairments were more severe in the CKD group, with MDS-UPDRS III scores of 42.8±8.5 compared to 34.6±7.2 in the control group (p<0.001). In patients with CKD, axial symptoms, including gait disturbances, postural instability, and bradykinesia, were more prominent, while resting tremor was less evident. Cognitive function assessments revealed a decline in performance in patients with CKD: MMSE scores averaged 24.8±2.1, compared with 26.5±1.8 in the control group (p<0.05), and MoCA scores averaged 20.6±3.4, compared with 25.4±2.2 (p<0.001), respectively. Among the CKD patients, 83.8% exhibited mild cognitive impairment (MoCA< 26), contrasting with 38.7% in the control group. Specifically, executive, visual-spatial, attention, and memory functions were significantly impacted. A positive correlation was found between eGFR and total MoCA scores (rS=0.48; p=0.005). Furthermore, non-motor manifestations were more common in the CKD group, with rates of depression at 64.5% vs. 38.7%, anxiety at 58.1% vs. 32.2%, constipation at 74.2% vs. 51.6%, daytime sleepiness at 54.8% vs. 25.8%, and orthostatic hypotension at 38.7% vs. 19.4% (p<0.05). Conclusions. The presence of CKD is associated with a more severe motor and cognitive phenotype in Parkinson’s disease, predominantly characterized by axial dysfunction and diminished executive functions. These findings highlight the importance of assessing renal function when evaluating the progression of Parkinson’s disease.