Relationship of Glycated Hemoglobin with Urinary Albumin-Creatinine Ratio and eGFR in Patients with Type 2 Diabetes Mellitus
TL;DR
Poor glycemic control is strongly associated with increased albuminuria and declining renal function in patients with T2DM, and routine monitoring of HbA1c, uACR, and eGFR may facilitate early identification of diabetic kidney disease.
Abstract
Background: Diabetic kidney disease (DKD) is one of the most common microvascular complications of type 2 diabetes mellitus (T2DM) and represents a major cause of chronic kidney disease (CKD) and end-stage renal disease (ESRD) worldwide. Glycated hemoglobin (HbA1c) is an established biomarker of long-term glycemic control and is routinely used to assess glycemic status in patients with T2DM. However, the association between HbA1c levels and key indicators of renal function, particularly the urinary albumin-to-creatinine ratio (uACR) and estimated glomerular filtration rate (eGFR), remains incompletely characterized, particularly among Indian patients with T2DM. Evaluating these relationships may improve understanding of the association between long-term glycemic control and the development and progression of DKD in this population. Methods: This cross-sectional observational study was conducted at a tertiary care center in Dehradun, India. A total of 100 patients with T2DM aged 35-70 years were enrolled. Clinical characteristics, HbA1c, uACR, eGFR, lipid profile, and comorbidities were assessed. Associations between HbA1c, uACR, and eGFR were analysed using descriptive statistics and correlation analysis. Multivariable binary logistic regression was performed to identify factors independently associated with reduced renal function, defined a priori as eGFR < 60 mL/min/1.73 m² (KDIGO Stage 3a or worse) at the time of the cross-sectional assessment. Results: The mean age of participants was 55.2 ± 8.5 years, and 55% were male. Increasing HbA1c levels were significantly associated with higher uACR values and lower eGFR (both p<0.001). Mean uACR increased progressively from 32.1 ± 12.4 mg/g among patients with HbA1c <7% to 412.8 ± 102.6 mg/g among those with HbA1c >9%. Similarly, eGFR declined significantly with worsening glycemic control. Patients with macroalbuminuria demonstrated the highest HbA1c levels and the lowest eGFR values. Factors independently associated with reduced eGFR (< 60 mL/min/1.73 m²) in the cross-sectional multivariable model included HbA1c > 8% (adjusted OR 3.8, 95% CI 2.1–6.9), hypertension (aOR 2.9, 95% CI 1.8–4.7), current smoking (aOR 2.4, 95% CI 1.6–3.5), obesity (aOR 2.1, 95% CI 1.4–3.2), and age > 60 years (aOR 1.8, 95% CI 1.2–2.7). Conclusions: Poor glycemic control is strongly associated with increased albuminuria and declining renal function in patients with T2DM. Routine monitoring of HbA1c, uACR, and eGFR may facilitate early identification of diabetic kidney disease. Prospective longitudinal studies are required to establish causality and to evaluate whether tighter glycaemic control reduces the risk of progression to renal impairment. Key words: Type 2 Diabetes Mellitus; Glycated Hemoglobin (HbA1c); Urinary Albumin-Creatinine Ratio (uACR); Estimated Glomerular Filtration Rate (eGFR); Diabetic Kidney Disease.