Carbohydrate metabolism and lipid profile in patients with Parkinson’s disease with subthalamic deep brain stimulation

Abstract

Aim of the study. Assessment of potential effect of subthalamic nucleus deep brain stimulation (STN-DBS) on glucose metabolism in patients with Parkinson’s disease (PD). Clinical rationale for the study. Although a valuable alternative to pharmacotherapy in advanced PD, STN-DBS is thought to negatively affect the cardiometabolic profile of patients (including body mass, lipid profile). Exacerbation of glucose metabolism dysregulation after DBS could therefore be assumed. Material and methods. Two groups of patients with Parkinson’s disease were included: 20 treated pharmacologically (PHT) and 20 newly qualified for STN-DBS (DBS) — with the first assessment prior to surgery, and the second 11 months after surgery on average. Body mass index (BMI), plasma concentrations of total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol (HDL-C), triglycerides (TG) and glucose levels during a three-point oral glucose tolerance test were measured three times (median intervals between visits 12 and 14 months respectively). Results. Significant differences between the two groups were noted with respect to changes in BMI, and serum concentration of TG and HDL-C over the course of the study. In the DBS group, a significant increase in BMI (26.42 vs. 27.24 kg/m2, p = 0.03) and TG level (103.8 vs. 142.8 mg/dL, p < 0.001) with a simultaneous decrease in HDL-C level (54.4 vs. 46 mg/dL, p < 0.01) was observed. Mean glucose level after oral glucose administration was lower in the DBS than in the PHT group (147.4 vs. 120.2 mg/dL, p = 0.03 after one hour and 109.9 vs. 82.3 mg/dL, p < 0.01 after two hours) during the second visit. Also inter-visit changes in fasting glucose levels (8.4 mg/dL in the PHT group and –5.8 mg/dL in the DBS group, p = 0.02) differed over the study duration. Conclusions. Our observations are similar to previous ones indicating less favourable changes in BMI and some lipid fractions in patients treated surgically. Interestingly, such a trend was not observed for glucose metabolism parameters, suggesting that mechanisms other than simple body mass changes are involved in early biochemical changes after STN-DBS in PD patients. Clinical implications. The metabolic consequences of DBS require further investigation as an additional factor potentially affecting the outcome of therapy, and routine patient follow-up should not be limited to neurological and psychological assessments.