Deep brain stimulation may reduce the relative risk of clinically important worsening in early stage Parkinson's disease

Abstract Background The Vanderbilt pilot trial of deep brain stimulation (DBS) in early Parkinson's disease (PD) enrolled patients on medications six months to four years without motor fluctuations or dyskinesias. We conducted a patient-centered analysis based on clinically important worsening of motor symptoms and complications of medical therapy for all subjects and a subset of subjects with a more focused medication duration. Continuous outcomes were also analyzed for this focused cohort. Methods A post hoc analysis was conducted on all subjects from the pilot and a subset of subjects taking PD medications 1–4 years at enrollment. Clinically important worsening is defined as both a ≥ 3 point increase in UPDRS Part III and a ≥ 1 point increase in Part IV. Results DBS plus optimal drug therapy (DBS + ODT) subjects experienced a 50–80% reduction in the relative risk of worsening after two years. The DBS + ODT group was improved compared to optimal drug therapy (ODT) at each time point on Total UPDRS and Part III (p = 0.04, p = 0.02, respectively, at 24 months). Total UPDRS, Part IV, and PDQ-39 scores significantly worsened in the ODT group after two years (p