Biochemical and Metabolic Profiles in Gad-Positive Versus Gad-Negative Type 2 Diabetes Mellitus Patients in Benin City, Nigeria
Keywords:
Biochemical profiles, C-peptide, GAD-65 autoantibodies, LADA, Lipid profile, Nigeria, Type 2 diabetes mellitusAbstract
The autoimmune subtype of diabetes in adults, characterized by the presence of glutamic acid decarboxylase-65 (GAD- 65) autoantibodies, may present with a distinct biochemical and metabolic phenotype compared to classical type 2 diabetes mellitus (T2DM). Data from sub-Saharan Africa on the metabolic correlates of GAD positivity remain limited. This study compared biochemical and metabolic profiles, including glycemic control, lipid parameters, C-peptide levels, and microalbuminuria, between GAD-positive and GAD-negative patients with apparent T2DM attending the University of Benin Teaching Hospital (UBTH), Benin City, Nigeria. A descriptive cross-sectional study was conducted among 240 consecutively recruited T2DM patients. Fasting blood samples were analyzed for GAD-65 autoantibodies, C-peptide, HbA1c, fasting blood glucose, and a full lipid profile. GAD positivity was defined as a titer of 0.62 ng/ml or above. Student t-test, Mann-Whitney U test, and chi-square tests were used for comparisons; a p value of 0.05 or less was considered statistically significant. Of 240 patients, 67 (27.9%) were GAD-positive. GAD-positive patients had significantly lower median C-peptide (0.40 IQR 0.80 ng/ml vs. 0.60 IQR 1.00 ng/ml, p=0.050) and a higher prevalence of insulinopenia (35.8% vs. 23.7%). Mean serum triglycerides were significantly lower in GAD-positive patients (143.00 vs. 188.95 mg/dl, p=0.025). No significant differences were found in HbA1c, fasting blood glucose, other lipid fractions, or microalbuminuria. GAD-positive T2DM patients demonstrated greater beta-cell dysfunction and lower triglyceride levels, consistent with an autoimmune diabetic phenotype. Routine GAD antibody and C-peptide screening is recommended for T2DM patients in Nigeria.
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