Role of Glycemic Control in Reducing Microvascular Complications in Type 2 Diabetes Mellitus

Abstract

Background: Microvascular complications contribute significantly to morbidity in type 2 diabetes mellitus (T2DM). This study aimed to evaluate the relationship between glycemic control and the development and progression of microvascular complications in patients with T2DM. Methods: A prospective, observational cohort study was conducted at a tertiary care center, enrolling 120 adults with T2DM stratified by baseline HbA1c (<7.0%, 7.0- 8.5%, and >8.5%). Participants were followed for 3 years with regular assessments of nephropathy, retinopathy, and neuropathy. The primary outcome was a composite of incident or worsening microvascular complications. Results: The primary composite outcome occurred in 37.5% of participants overall, with significant differences across glycemic control categories: 21.1% in the HbA1c <7.0% group, 35.0% in the HbA1c 7.0-8.5% group, and 58.8% in the HbA1c >8.5% group (p=0.004). After adjustment for confounders, the hazard ratios for the primary outcome were 1.76 (95% CI: 0.97-3.20, p=0.064) for the HbA1c 7.0-8.5% group and 3.12 (95% CI: 1.73-5.63, p<0.001) for the HbA1c >8.5% group, compared to the HbA1c <7.0% group. Each 1% increase in HbA1c was associated with a 42% increased risk of the composite outcome (adjusted HR: 1.42, 95% CI: 1.25-1.61, p<0.001). Other significant predictors included diabetes duration (adjusted HR per 5 years: 1.38, p<0.001), systolic blood pressure (adjusted HR per 10 mmHg: 1.25, p=0.001), and baseline microvascular status. Conclusion: This study demonstrates a strong, graded association between glycemic control and microvascular complications in T2DM. Maintaining HbA1c below 7.0% was associated with significantly lower complication rates compared to higher levels. These findings support current guidelines recommending individualized glycemic targets, generally aiming for HbA1c <7.0% in most patients to reduce microvascular risk.