Clinical Profile of Nonproteinuric Kidney Disease in Type 2 Diabetic Patients in India

BACKGROUND: Diabetic kidney disease (DKD) is the commonest cause of end-stage renal disease (ESRD) across the world. Development of microalbuminuria is the earliest marker of DKD and predicts progressive decline in estimated glomerular filtration rate (eGFR). However, recent evidence has suggested that a significant proportion of type 2 diabetic patients have chronic kidney disease (CKD) without proteinuria. METHODS: In this single-center, prospective observational study, 400 consecutive type 2 diabetic patients with either overt proteinuria (>500 mg/day) and/or renal dysfunction eGFR <60 ml/min/1.73 m(2)) were recruited. Baseline demographic and clinical data were recorded. eGFR and proteinuria were recorded at 6 months and 1 year. Patients with proteinuric (proteinuria >0.5 g/day) and nonproteinuric phenotypes were compared for progression of renal dysfunction in terms of doubling of serum creatinine and need for dialysis. RESULTS: In our study cohort, 106 (26.5%) were nonproteinuric. Both the groups were similar in terms of gender, duration of diabetes, comorbidities, body mass index (BMI), blood pressure control, and glycemic control. The nonproteinuric group was older (56.5 ± 2.1 vs. 54.7 ± 11.6 years, P = 0.012), had lesser prevalence of diabetic retinopathy (49 [46.2%] vs. 218 [74.1%], P < 0.001), higher hemoglobin levels (11.3 ± 1.7 vs. 10.5 ± 2.0 g/dl, P < 0.001), and higher cholesterol levels (169.3 ± 43.3 vs 157.1 ± 58.1 mg/dl, P = 0.025). The nonproteinuric phenotype had higher eGFR at baseline, 6 months, and 1 year. However, doubling of serum creatinine (10 [9.4%] vs. 48 [16.3%]) and progression to ESRD (5 [4.7%] vs. 19 [6.5%], P = 0.159) were not different between the two phenotypes. CONCLUSION: Nonproteinuric DKD is common. Patients with nonproteinuric DKD tend to be older with a slower decline in eGFR.