Original Abstract

AIMS: To investigate the association between use of GLP-1 receptor agonists and incident Parkinson's disease. MATERIAL AND METHODS: Cohort study using data from nationwide registers in Denmark, Norway and Sweden and an active-comparator, new-user design. We included 158 961 new users of GLP-1 receptor agonists and 188 065 new users of sulfonylureas, aged 45 years or older. Liraglutide accounted for 72.9% of GLP-1 receptor agonist follow-up time, followed by semaglutide (13.4%), exenatide (7.3%), dulaglutide (5.1%) and lixisenatide (1.3%). The primary outcome was incident Parkinson's disease, defined as a first-ever diagnosis of Parkinson's disease (ICD-10 G20) or Parkinson's disease dementia (ICD-10 F02.3) in national patient registers. Cox regression with propensity score weighting was used to estimate hazard ratios (HRs) and control for confounding. RESULTS: Mean age was 65 years and 43% were female. Incidence rates for Parkinson's disease were 5.2 and 8.0 per 10 000 person-years among GLP-1 receptor agonist and sulfonylurea users, respectively (adjusted HR 0.81 [95% CI 0.68-0.96]). Results were consistent in a 2-year lag-time analysis (HR 0.84 [95% CI 0.70-1.02]) after excluding or censoring users of DPP-4 inhibitors at cohort entry or during follow-up (HR 0.74 [95% CI 0.60-0.93]) and in subgroup analyses by sex and age. CONCLUSION: In this large observational cohort study, use of GLP-1 receptor agonists compared with sulfonylureas was associated with a lower risk of incident Parkinson's disease. These findings support a potential neuroprotective role of GLP-1 receptor agonists, though replication in additional studies is needed.