Glucose dysregulation in advanced Parkinson's Disease: too much glucose or not enough insulin?

Background and aims: Glucose metabolism has recently been reported to be altered in Parkinson’s Disease (PD) as a non-motor consequence of the disease. Since insulin pancreatic production and secretion is modulated by the autonomic nervous system, the severity of dysautonomia in PD could be linked with blood glucose dysregulation. We aimed to detect changes in glucose regulation in PD patients compared to healthy controls in response to oral glucose intake. Methods: Blood glucose and insulin kinetics during a 75-g Oral Glucose Tolerance Test were compared between 50 PD patients and 50 healthy controls (CT) matched for Body Mass Index (BMI), age and sex. Potential relationships between changes in glucose kinetics and clinical parameters were analyzed including PD severity and autonomic function using SCOPA-AUT (Scales for Outcomes in Parkinson’s disease, Autonomic dysfunction). Results: Blood glucose was significantly higher at T90 (p=0.04) and T150 (p=0.01) in PD patients compared to CT. Moreover, the total area under time curve for blood glucose was significantly higher in PD patients compared to healthy controls (1187±229 vs 1101±201 mmol.min.l-1; p=0.05). Simultaneously, no significant increase of insulin levels was observed in PD patients compared to controls. Higher blood glucose levels were associated with higher BMI (p