Could the performance of oral glucose tolerance test contribute to the brain health-focused care in multiple sclerosis?

BACKGROUND It has not been clarified yet if persons with multiple sclerosis (MS) are at increased risk to develop glucose metabolism dysregulation. The aims of the present study were to evaluate glucose metabolism characteristics in persons with MS and to compare it to the healthy individuals; to examine the association of glucose metabolism with the level of disability and its progression. METHODS The study enrolled 78 patients with MS and 26, comparable for age, gender and body mass index (BMI), healthy controls (HC). Disability and its progression were evaluated by the Expanded Disability Status Scale (EDSS) score, progression index (PI) and multiple sclerosis severity score (MSSS). All participants performed an oral glucose tolerance test (OGTT). Insulin and lipid parameters were analyzed. RESULTS Fasting glucose concentrations (5.3±0.7 in MS patients vs. 4.5±0.9 mmol/L in HC, p=0.001) and 2 hour post-load glucose concentrations were statistically significantly higher in MS patients compared with controls. Glucose levels at all different time points during OGTT, baseline insulin, Homeostasis model assessment of insulin resistance (HOMA-IR), total cholesterol and LDL were statistically significantly (p<0.05) associated with MS, in univariable logistic regression analysis. Glucose level at 120' was independently associated with MS (OR=3.937, 95% CI 1.178-13.159, p=0.026), in the multivariable model. The prevalence of IR was 64.1% in the MS group compared to 30.8% in the control group (p=0.008), based on HOMA-IR. EDSS and Multiple sclerosis severity score (MSSS) were associated with glucose levels at different time points (p<0.05). According to the ROC analysis, best cut-off value for HOMA-IR is 2.3, providing both sensitivity and specificity of 66.7% in discriminating persons with MS and HC. CONCLUSION Our results demonstrate the presence of higher prevalence of IR in MS patients compared to healthy individuals, and strong association between impaired glucose metabolism and disability. Finally, it has to be emphasized that further studies are warranted to confirm our findings implicating that MS patients have significantly higher risk of impaired glucose metabolism, which could suggest the potential importance of the performance of OGTT in patients with this disorder.