Changes in Glucose Regulation in Parkinson Disease
Dysglycemia in Parkinson's may be a result of impaired adaptive insulin secretion because of dysautonomia.
Patients with Parkinson disease (PD) who are nondiabetic have impaired glucose control compared with healthy controls, according to the results of a controlled, cross-sectional study (ClinicalTrials.gov identifier: NCT01114321) that was conducted in the Movement Disorders Unit of the University Hospital of Clermont-Ferrand in France. Findings from the study were published in Parkinsonism and Related Disorders.
The investigators sought to detect changes in glucose regulation in patients with moderate to severe PD in response to oral glucose intake. Blood glucose levels and insulin kinetics were compared in 50 patients with PD and 50 healthy control patients during a 75-g Oral Glucose Tolerance Test (OGTT). Patients with PD and control patients were matched with respect to age, sex, and body mass index. A self-assessment questionnaire, the Scales for Outcomes in Parkinson's disease, Autonomic dysfunction (SCOPA-AUT), was used to analyze potential associations between changes in glucose kinetics and clinical parameters, including PD severity and autonomic function.
All participants had to drink the 75-g solution used in the OGTT within 5 minutes. After this, blood glucose and insulin levels were measured at 30 minutes (T30), 60 minutes (T60), 90 minutes (T90), 120 minutes (T120), 150 minutes (T150), and 180 minutes (T180). Blood glucose levels were significantly higher at T90 (P =.04) and T150 (P =.01) among patients with PD vs healthy control patients.
In addition, the total area under the curve for blood glucose concentrations was significantly greater in patients with PD compared with healthy control patients (1187±229 vs 1101±201 mmol/min/L; P =.05). At the same time, there was no significant increase in insulin levels observed among patients with PD compared with control patients.
Higher blood glucose levels were significantly associated with higher body mass index (P <.001), female sex (P <.033), longer duration of PD (P =.001), higher SCOPA-AUT scores (P =.017), and lower dose of dopaminergic agents (P =.023).
The investigators concluded that the impairment in glucose control observed among patients with moderate to severe PD who do not have diabetes is the result of an impairment in their adaptive insulin response, which may be a novel nonmotor result of PD-associated dysautonomia. A major limitation of the current study is the fact that level of physical activity, which is known to play a large role in the regulation of glucose metabolism, was not evaluated.
Marques A, Dutheil F, Durand E, et al. Glucose dysregulation in Parkinson's disease: Too much glucose or not enough insulin? [published online May 31, 2018]. Parkinsonism Relat Disord. doi: 10.1016/j.parkreldis.2018.05.026