Sex disparity in patients with Parkinson's disease treated using deep brain stimulation.
Objective: Studies have suggested that there may be sex differences in the preoperative characteristics and postoperative outcomes of patients with Parkinson's disease (PD) treated with subthalamic nucleus (STN) deep brain stimulation (DBS). Authors of this study aimed to reveal differences in preoperative and 1-year postoperative motor symptoms, dopaminergic medication use, and quality of life (QOL) domains between men and women who had undergone STN DBS.
Methods: In this retrospective cohort study, the authors evaluated patients who underwent bilateral STN DBS at a single center from 2008 to 2023. Motor symptoms were measured using the Unified Parkinson's Disease Rating Scale Part III (UPDRS-III), levodopa equivalent daily dose (LEDD) was used to measure the dosage of dopaminergic medications, and the 39-Item Parkinson's Disease Questionnaire (PDQ-39) was used to determine QOL outcomes. Exploratory linear mixed-effect models were used to investigate sex and time interactions for the UPDRS-III, LEDD, and PDQ-39 scores.
Results: Ninety-four patients, 26 females and 68 males, were included in the study. Preoperatively, women presented with a significantly longer disease duration (p = 0.014), greater UPDRS-III off-medication scores (p < 0.001), lower LEDDs (p = 0.001), and worse PDQ-39 mean total score (p < 0.001). One year postoperatively, after adjusting for disease duration, age, UPDRS-III off scores, and LEDD, there was a significant sex and time interaction for the cognition domain of the PDQ-39, which showed worsening over time in women (p = 0.009). There was no significant sex and time interaction in the UPDRS-III off-medication/on-stimulation scores.
Conclusions: Although STN DBS is equally clinically efficacious for both sexes, women are treated later in the disease course. Preoperatively, women present during more advanced stages of PD with worse motor symptoms and a lower QOL. Postoperatively, women score worse on the cognition index, a proxy for mood rather than cognition.