Normoalbuminuric renal insufficient diabetic patients: A lower risk group

Abstract

OBJECTIVE- About 20% of diabetic patients with Chronic Kidney Disease (CKD) detected from the new ADA recommendations (Albumin Excretion Rate (AER) >30 mg/24H or estimated Glomerular Filtration Rate (GFR) <60 mL/min/1.73m²) may be normoalbuminuric. Do the characteristics and outcome differ for subjects with and without albuminuria?

RESEARCH DESIGN AND METHODS- Eighty-nine patients with diabetes and a MDRD-estimated GFR (MDRD e-GFR) <60 underwent a 51Cr-EDTA i-GFR determination, and were followed up for 38±11 months.

RESULTS- The mean MDRD e-GFR (41.3±13.1 mL/min/1.73m²) did not significantly differ from the i-GFR (45.6±29.7). Fifteen (17%) of the subjects were normoalbuminuric. Their i-GFR did not differ from the albuminuric and from their MDRD e-GFR, although their serum creatinine was lower (122±27 μmol/L vs 160±71, p<0.05): 71% would not have been detected by measuring serum creatinine (sCr) alone. They were less affected by diabetic retinopathy, and their HDL-cholesterol and hemoglobin were higher (p<0.05 vs albuminuric). None of the CKD normoalbuminuric subjects started dialysis (microalbuminuric: 2/36, macroalbuminuric: 10/38) or died (microalbuminuric: 3/36, macroalbuminuric: 7/38) during the follow-up period (Logrank test: p<0.005 for death or dialysis), and their AER and sCr were stable after 38 months, whereas the AER increased in the microalbuminuric patients (p<0.05) and the sCr increased in the macroalbuminuric (p<0.01).

CONCLUSIONS- Although their sCr is usually normal, most of the normoalbuminuric diabetic subjects with CKD according to a MDRD e-GFR below 60 do really have a GFR below 60. However, as expected due to normoalbuminuria and other favorable characteristics, their risk for CKD progression or death is lower.