Comparative Effectiveness of Carbidopa–Levodopa Enteral Suspension and Deep Brain Stimulation on Parkinson’s Disease-Related Pill Burden Reduction in Advanced Parkinson’s Disease: A Retrospective Real-World Cohort Study

INTRODUCTION: In advanced Parkinson’s disease (PD), a high pill burden is associated with poor compliance, reduced control of symptoms, and decreased quality of life. We assessed the impact of carbidopa–levodopa enteral suspension (CLES) and deep brain stimulation (DBS) on PD-related pill burden. METHODS: A retrospective cohort analysis was conducted in the IBM MarketScan and Medicare Supplemental databases. Patients with advanced PD, taking only PD medications, and initiating CLES or DBS between 9 January 2015 and 31 July 2019 were identified. CLES patients were matched to DBS patients in a 1:3 ratio based on a propensity score to balance patient characteristics. Pill burden was measured as a 30-day average number of PD-related pills per day and was captured monthly. Pill-free status was evaluated as the percentage of patients receiving CLES or DBS monotherapy. Descriptive statistics were used to compare pill counts and assess the proportion of patients on monotherapy at 6 and 12 months after initiating CLES or DBS. RESULTS: The cohorts included 34 CLES patients matched to 97 DBS patients. A significant reduction in PD-related pill burden was observed at 6 months after initiation of CLES or DBS (∆CLES: −5.62, p < 0.0001; ∆DBS: −1.48, p = 0.0022). PD-related pill burden reduction in CLES patients was significantly greater than in matched DBS patients at 6 months (∆: −4.14, p < 0.0001), which was sustained at 12 months after initiation. At 12 months, nearly three times more CLES patients were pill free than DBS patients (29.41% and 10.31%, respectively, p = 0.0123). CONCLUSIONS: Device-aided therapies such as CLES and DBS are effective in significantly reducing PD-related pill burden. Patients treated with CLES were more likely to achieve pill-free status than patients receiving DBS.