Rethinking age barriers in Parkinson's disease for deep brain stimulation

The age cutoff for subthalamic nucleus (STN) deep brain stimulation (DBS) in Parkinson's disease (PD) has been a contentious issue. Typically, it is offered to patients younger than 70 years. This study, however, aims to compare DBS efficacy outcomes between patients with age ≥70 years and those aged <70 years, potentially paving the way for a more inclusive approach to DBS in PD treatment.

This study is a retrospective, cross-sectional cohort study of PD patients who underwent STN-DBS between 2002 and 2019. The analysis included a comprehensive range of sociodemographic and clinical variables. The primary outcome was the reduction in Movement Disorder Society - Unified Parkinson's Disease Rating Scale part III (MDS-UDPRSIII). The secondary outcome was reduced levodopa equivalent daily dose (LEDD). The statistical analysis was performed in SPSS-25, with a stringent threshold of p < 0.05, to reject the null hypothesis, ensuring the robustness of our findings.

From a cohort of 360 patients with PD who underwent STN-DBS, we included 15 patients 70 years or older with a mean age of 70.4 ± 0.9 years, a mean disease duration of 13.0 ± 2.8 years, and 61 patients younger than 70 years old with a mean age of 61.2 ± 6.6 years; median disease duration of 13.0 [IQR:10.0]. No significant statistical differences were found in the MDS-UPDRS-III score on both groups at the at baseline (p = 0.480), at one year (p = 0.341) and at three years of follow-up (p = 0.117). In both groups, postoperative reduction of LEDD was similar (35.7 [IQR: 33.91] vs 31.6 ± 18.3); (p = 0.960) in patients with age 70 years or older and those younger than 70 years respectively; nevertheless, patients with 70 years or older had higher LEDD at three years (p < 0.001).

Our study found no significant differences in the MDS-UPDRS-III in groups younger and older than 70 at baseline, at one year and at three years of follow-up. However, higher LEDD was necessary in the elderly group. This highlights the urgent need for more inclusive research to better understand the cost-effectiveness of DBS in this population. By conducting such research, we can ensure that all PD patients, regardless of age, have access to the most effective treatments.