549-P: Renal Outcome of Patients with Type 2 Diabetes Exhibiting Normoalbuminuric Renal Insufficiency

Recent studies have identified a unique subgroup of patients with type 2 diabetes exhibiting reduced renal function in spite of being normoalbuminuric; however, information is limited regarding the clinical course of these patient. Here, we evaluated renal outcome of patients with normoalbuminuric renal insufficiency. This was a single-center, historical cohort study. We studied 7,152 adult Japanese patients with type 2 diabetes (mean age: 61 years, men: 64%) who had never undergone renal replacement therapy (RRT). The subjects were classified into 6 groups based on the baseline estimated glomerular filtration rate (eGFR): ≥ 60 or < 60 mL/min/1.73 m²and urinary albumin-to-creatinine ratio: ACR (<30: normoalbuminuria, 30-299: microalbuminuria, or ≥ 300 mg/g: macroalbuminuria). Two separate endpoints were defined as follows: 1) ≥ 30% decline in eGFR from the baseline value or initiation of RRT, whichever came first, and 2) annual decline in eGFR, estimated using a linear mixed-effect model. During a median follow-up of 5.7 years, 1,374 patients reached the first endpoint. The adjusted hazard ratios (vs. patients with normal eGFR and normoalbuminuria [n= 3,881]) for patients with reduced eGFR and normoalbuminuria (n= 823), normal eGFR and microalbuminuria (n= 1,010), reduced eGFR and microalbuminuria (n= 508), normal eGFR and macroalbuminuria (n= 235), and reduced eGFR and microalbuminuria (n= 695) were 1.55, 2.74, 4.15, 10.00, and 29.02, respectively (all p< 0.001). The adjusted annual decline in eGFR (least square mean ± standard error) in patients with reduced eGFR and normoalbuminuria was 0.66 ± 0.10 mL/min/1.73 m²/year, which was significantly lower than those in other 5 groups (p< 0.001).

In conclusion, patients with type 2 diabetes manifesting normoalbuminuric renal insufficiency are likely to have a better kidney prognosis, with an extremely slow decline rate of renal function.