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

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.