Deep brain stimulation in early-stage Parkinson disease

ObjectiveTo report 5-year outcomes from the subthalamic nucleus (STN) deep brain stimulation (DBS) in early-stage Parkinson disease (PD) pilot clinical trial.MethodsThe pilot was a prospective, single-blind clinical trial that randomized patients with early-stage PD (Hoehn & Yahr II off medications) to receive bilateral STN DBS plus optimal drug therapy (ODT) vs ODT alone (IDEG050016, NCT0282152, IRB040797). Participants who completed the 2-year trial participated in this observational follow-up study, which included annual outpatient visits through 5 years. This analysis includes 28 patients who were taking PD medications for 6 months to 4 years at enrollment. Outcomes were analyzed using both proportional odds logistic regression and linear mixed effects models.ResultsEarly STN DBS + ODT participants required lower levodopa equivalent daily doses (p = 0.04, β = −240 mg, 95% confidence interval [CI] −471 to −8) and had 0.06 times the odds of requiring polypharmacy at 5 years compared to early ODT participants (p = 0.01, odds ratio [OR] 0.06, 95% CI 0.00 to 0.65). The odds of having worse rest tremor for early STN DBS + ODT participants were 0.21 times those of early ODT participants (p < 0.001, OR 0.21, 95% CI 0.09 to 0.45). The safety profile was similar between groups.ConclusionsThese results suggest that early DBS reduces the need for and complexity of PD medications while providing long-term motor benefit over standard medical therapy. Further investigation is warranted, and the Food and Drug Administration has approved the conduct of a prospective, multicenter, pivotal clinical trial of DBS in early-stage PD (IDEG050016).Classification of evidenceThis study provides Class II evidence that DBS implanted in early-stage PD decreases the risk of disease progression and polypharmacy compared to optimal medical therapy alone.