Decline in the estimated glomerular filtration rate (eGFR) following metabolic control and its relationship with baseline eGFR in type 2 diabetes with microalbuminuria or macroalbuminuria

Aims Relationship between baseline eGFR and the rate of decline in eGFR was investigated in diabetic kidney disease. Materials and methods Patients with type 2 diabetes with microalbuminuria (MI) (n = 124) or macroalbuminuria (MA) (n = 81) received team-based medical care to prevent the development of diabetic kidney disease. The decline in eGFR over 4 years, divided into the first year and subsequent 3 years, was estimated by linear-mixed modeling. Results The eGFR showed a rapid decline during the first year, followed by a slower decline. On multiple regression analysis, the baseline eGFR was positively correlated with HbA1c in MI and negatively correlated with carotid plaque in MI and in MA. Subsequent eGFR decline following 1-year intervention was negatively correlated with the baseline eGFR and HbA1c level at 1 year in MI, whereas it was positively correlated with baseline eGFR and negatively correlated with the amount of proteinuria at 1 year in MA. Even in maintained baseline eGFR(>= 60 ml/min/1.73 m(2)) at the first year, when HbA1c >= 7.5%, eGFR reduction rate and years to ESKD were much faster and shorter, compared to the group of HbA1c < 7.5% [- 3.44 (SE 1.137) vs. - 1.695 (SE 0.431) ml/min/1.73 m(2)/year, and 19.4 vs. 35.7 years, respectively]. In MA, lower eGFR (< 60 ml/min/1.73 m(2)) and higher proteinuria (>= 2.25 g/gCre) had a much faster eGFR decline and shorter time to ESKD, compared to the group of maintained eGFR and lower proteinuria (< 2.25 g/gCre) [- 5.240 (SE 1.537) vs. - 2.67 (SE 0.997) ml/min/1.73 m(2)/year, and 4.41 vs. 22.8 years, respectively]. Conclusions In MI, even in maintained eGFR, the continued increase in eGFR in response to hyperglycemia (HbA1c >= 7.5%) led to a faster decline in renal function and in MA, lower eGFR, with an increase in proteinuria, contributed to rapid decline of renal function.