Euglycemia Indicates Favorable Motor Outcome in Parkinson's Disease

Background The interplay between glycemic control and Parkinson's disease (PD) has long been recognized but not fully understood. Objectives To investigate the association of glycated hemoglobin (HbA1c) levels with motor and cognitive symptom progression in a prospective PD cohort. Methods Of 244 PD patients, 17 had low HbA1c (≤30 mmol/mol), 184 were euglycemic (HbA1c 31–41 mmol/mol), 18 had high HbA1c (HbA1 ≥42 mmol/mol), and 25 had diabetes mellitus (DM). Survival analysis was applied on time until Hoehn and Yahr stage ≥3 (motor outcome) and until mild cognitive impairment. Results Low HbA1c (HR 2.7; 95% CI 1.3–6; P = 0.01) as well as high HbA1c (HR 3.6; 95% CI 1.5–8.9; P = 0.005) but not DM were independent predictors of unfavorable motor outcome. Conclusions Both high and low HbA1c levels may be associated with motor symptom progression in PD; however, further studies are needed to confirm these findings and increase understanding regarding causality. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society