The impact of depressive symptoms on 5-year all-cause mortality in patients with parkinson’s disease treated with and without deep brain stimulation

This retrospective single-center study evaluated the impact of depressive symptoms on survival in patients with Parkinson's disease (PD) treated with deep brain stimulation (DBS) or best medical treatment (BMT). A total of 421 patients (337 BMT, 84 DBS) from the Medical University of Vienna were included, with data collected between 1999 and 2024. Depressive symptoms were assessed using the Geriatric Depression Scale (GDS), and cognitive performance was evaluated using subtests of the Neuropsychological Test Battery Vienna (NTBV). A Cox proportional hazards model was applied to examine the predictive value of depressive symptoms and additional covariates, including age, gender, education, and cognitive function. Increasing age and male sex were significant risk factors for increased mortality. While depressive symptoms showed an initial association with survival, their predictive strength diminished when cognitive and demographic factors were included. Cognitive performance, particularly attention and executive functioning, assessed by NTBV-15, showed significant protective effects. Five-year survival was 73.4% in the BMT group and 88.2% in the DBS group (p < .05), though therapy type itself was not a significant predictor in the regression model. These findings suggest that depressive symptoms may contribute to mortality in PD patients but appear to be outweighed by cognitive and demographic variables. Cognitive assessment may offer additional prognostic value in long-term outcome prediction.