Hypothesis / aims of study
Parkinson's disease (PD) is a neurodegenerative disease clinically characterized by bradykinesia, rigidity, and rest tremor. It is well known that non-motor symptoms, including lower urinary tract symptoms (LUTS), are prevalent and severe in PD patients. Deep brain stimulation (DBS) is performed for advanced stages of PD in patients presenting with severe motor complications. Although it is well known that DBS dramatically improves motor complications, its effect on LUTS remains to be elucidated. Furthermore, recent studies have typically investigated the effects of DBS through changes in quality of life (QOL) scores. However, it is unclear to what extent LUTS affects the quality of life of PD patients. We aimed to clarify the association between LUTS-related QOL and health-related QOL in PD patients undergoing DBS.
Study design, materials and methods
We retrospectively reviewed the scores of the Overactive Bladder Symptom Scale (OABSS), International Prostate Symptom Score (IPSS), and IPSS-QOL in PD patients who underwent subthalamic nucleus (STN)-DBS. Health-related quality of life (QOL) was evaluated using the Parkinson’s Disease Questionnaire (PDQ)-39. The evaluations were conducted before and after surgery (at three months and one year post-surgery). Correlation coefficients between lower urinary tract symptoms (LUTS) (OABSS and IPSS scores), IPSS-QOL, and the PDQ-39 score were calculated. As PDQ-39 comprises eight subcategories such as mobility, activities of daily living (ADL), emotional well-being, stigma, social support, cognition, communication, and bodily discomfort, we assessed the correlational coefficients between the subcategories of PDQ-39 and LUTS/IPSS-QOL. Additionally, we performed multivariable regression analysis to determine which subcategories of PDQ-39 contributed to IPSS-QOL.
Results
We examined 43 PD patients (mean age 63.7±0.8 years, mean disease duration 11.8±0.4 years) preoperatively. Post-operative evaluations were conducted in 24 PD patients three months and one year after surgery. OABSS significantly decreased one year after surgery (4.70→3.93, p=0.011, Cohen’s d=0.56). Although the score of IPSS tended to decrease after surgery without statistical significance (three months after surgery 6.81±0.81→6.31±1.13, p=0.602; one year after surgery 6.81±0.81→5.32±0.85, p=0.378), IPSS-QOL score significantly decreased three months after surgery (3.32±0.23→2.70±0.38, p=0.05, Cohen’s d=0.419) and one year after surgery (3.32±0.23→2.43±0.24, p=0.05, Cohen’s d=0.339). PDQ-39 summary index significantly improved three months (36.0±2.0% to 27.0±2.0%, p<0.01, Cohen’s d=0.46) and one year after surgery (36.0±2.0% to 25.0±2.0%, p=0.05, Cohen’s d=0.31). Pre-operative IPSS-QOL score and post-operative OABSS, IPSS, and IPSS-QOL score three months after surgery had significant positive correlational relationships with multiple subcategories of PDQ-39 (Table). Regarding the associations between LUTS, IPSS-QOL, and PDQ-39 subcategory, pre-operative IPSS-QOL had significant positive associations with the pre-operative PDQ-39 subcategory of social support (standardized beta =0.559, p=0.003).
Interpretation of results
This study revealed that STN-DBS significantly improved LUTS and IPSS-QOL, as well as health-related QOL as evaluated by the PDQ-39. It has been reported that STN-DBS increased maximum bladder capacity and inhibited detrusor overactivity, which might contribute to the improvement of OABSS [1]. It should be noted that both the scores of IPSS-QOL and PDQ-39 decreased significantly postoperatively in this study. Multivariable regression analysis suggested that IPSS-QOL had significant positive associations with the PDQ-39 subcategory of social support preoperatively. In PDQ-39, the sub-score of social support increases when PD patients feel that they have problems with their close personal relationships or lack support from their partner or family. In terms of health-related QOL, preoperative PD patients usually have severe motor complications and often require a lot of social support with toileting activities, leading to a higher score of IPSS-QOL.