Introduction: Bariatric surgery is an established intervention for obesity and its metabolic complications, including diabetes mellitus. However, most studies are from Western populations with limited data in Malaysia. This study evaluated glycemic status improvements and identified predictors of hemoglobin A1c (HbA1c) reduction at 12 months following bariatric surgery to contribute regional data to Southeast Asia. Methodology: This retrospective analysis included 110 patients who underwent bariatric surgery between 2015 and 2025. Pre- and post-operative parameters, including HbA1c, body mass index (BMI), and lipid profiles, were collected at 1, 3, 6, 9, and 12 months and evaluated as potential predictors of glycemic status improvement at 12 months. Univariate analysis followed by stepwise multivariate linear regression was performed to identify predictors of HbA1c improvement at 12 months. Regression coefficients (B), 95% confidence intervals, and p-values were reported. Results: The mean age was 40.5 years with a mean baseline BMI of 43.49 kg/m²; 58% were female. At baseline, 60.9% (n = 67) had diabetes, 30.9% (n = 34) prediabetes, and 8.2% (n = 9) normal HbA1c. In univariate analysis, baseline HbA1c (B = 0.579, p <0.001), age (B = −0.051, p = 0.034), and sex (B = 1.123, p = 0.044) were significantly associated with HbA1c change. In multivariate analysis, the final model identified baseline HbA1c, BMI difference at 12 months, and TG difference at 12 months as independent predictors of HbA1c change. Baseline HbA1c was the strongest predictor (B = 0.857, p <0.001) indicating that higher baseline HbA1c was associated with greater change over time. BMI difference at 12 months was also significantly associated with HbA1c change (B = 0.046, p = 0.016), indicating that greater weight loss contributed to improved glycemic control. Similarly, TG difference at 12 months was a significant predictor (B = 0.337, p = 0.023). The model explained 86.8% of the variation in HbA1c change (adjusted R² = 0.868). Conclusion Bariatric surgery resulted in significant weight loss and improvement in glycemic status at 12 months, with baseline HbA1c, BMI differences, and TG reductions emerging as key predictors of glycemic improvement in a Malaysian cohort.
Cohort Studies ; Bariatric Surgery