Long-term outcomes following deep brain stimulation for Parkinson's disease

OBJECTIVE Deep brain stimulation (DBS) is an effective treatment for several movement disorders, including Parkinson's disease (PD). While this treatment has been available for decades, studies on long-term patient outcomes have been limited. Here, the authors examined survival and long-term outcomes of PD patients treated with DBS. METHODS The authors conducted a retrospective analysis using medical records of their patients to identify the first 400 consecutive patients who underwent DBS implantation at their institution from 1999 to 2007. The medical record was used to obtain baseline demographics and neurological status. The authors performed survival analyses using Kaplan-Meier estimation and multivariate regression using Cox proportional hazards modeling. Telephone surveys were used to determine long-term outcomes. RESULTS Demographics for the cohort of patients with PD (n = 320) were as follows: mean age of 61 years, 70% male, 27% of patients had at least 1 medical comorbidity (coronary artery disease, congestive heart failure, diabetes mellitus, atrial fibrillation, or deep vein thrombosis). Kaplan-Meier survival analysis on a subset of patients with at least 10 years of follow-up (n = 200) revealed a survival probability of 51% (mean age at death 73 years). Using multivariate regression, the authors found that age at implantation (HR 1.02, p = 0.01) and male sex (HR 1.42, p = 0.02) were predictive of reduced survival. Number of medical comorbidities was not significantly associated with survival (p > 0.5). Telephone surveys were completed by 40 surviving patients (mean age 55.1 +/- 6.4 years, 72.5% male, 95% subthalamic nucleus DBS, mean follow-up 13.0 +/- 1.7 years). Tremor responded best to DBS (72.5% of patients improved), while other motor symptoms remained stable. Ability to conduct activities of daily living (ADLs) remained stable (dressing, 78% of patients; running errands, 52.5% of patients) or worsened (preparing meals, 50% of patients). Patient satisfaction, however, remained high (92.5% happy with DBS, 95% would recommend DBS, and 75% felt it provided symptom control). CONCLUSIONS DBS for PD is associated with a 10-year survival rate of 51%. Survey data suggest that while DBS does not halt disease progression in PD, it provides durable symptomatic relief and allows many individuals to maintain ADLs over long-term follow- up greater than 10 years. Furthermore, patient satisfaction with DBS remains high at long-term follow-up.