Increased Prevalence of Polyneuropathy in Parkinson’s Disease Patients: An Observational Study

BACKGROUND The independent contribution of levodopa exposure and Parkinson's disease (PD) to the risk of polyneuropathy is not established. OBJECTIVE This study investigated whether patients with newly diagnosed PD without previous exposure to antiparkinsonian drugs have higher prevalence of polyneuropathy than the general population. METHODS Using the UK General Practice Research Database, presence of polyneuropathy in the previous 3 years was assessed. RESULTS Of 5089 PD patients and 19,897 controls, polyneuropathy was confirmed in 15 PD patients (0.29% ) and 24 controls (0.12% ). Polyneuropathy prevalence was 2.4-fold higher in PD patients than controls. CONCLUSIONS In this observational study, PD patients had a higher prevalence of preexisting polyneuropathy that cannot be explained by adverse effects of antiparkinsonian drugs.