Prevalence and clinical significance of glutamic acid decarboxylase antibodies among young diabetic patients in Faisalabad, Punjab.

Glutamic acid decarboxylase (GAD) antibodies are markers of pancreatic beta-cell autoimmunity and play a critical role in understanding the autoimmune component of diabetes mellitus. Despite its importance for distinguishing autoimmune diabetes, limited data exists on GAD antibody among young patients. This study determined the prevalence and clinical significance of GAD antibodies among young diabetic patients in Faisalabad, Punjab, Pakistan. This cross-sectional study recruited diabetic patients aged ≤40 years from tertiary care hospitals of Faisalabad. Data were collected using a validated questionnaire, and GAD antibodies were measured using the chemiluminescence immunoassay. Among 506 patients (253 T1DM, 253 T2DM), GAD prevalence was 18.2%, significantly higher in T1DM (28.9%) versus T2DM (7.5%; p<0.001). Age at onset demonstrated good predictive value (AUC=0.714) with an optimal cutoff at 20 years (sensitivity=69.6%, specificity=69.3%). BMI showed predictive utility (AUC=0.702) with a cutoff at <23kg/m². Multivariate analysis also revealed younger age at onset (OR=3.2, 95% CI: 1.8-5.6) and lower BMI (OR=2.8, 95% CI: 1.6-4.9) significantly associated with GAD positivity. GAD antibodies are prevalent among young diabetic patients in Faisalabad, with significantly higher prevalence in T1DM. Younger onset age and lower BMI were significant predictors of GAD positivity but should be interpreted along with other clinical and biochemical factors.