High average blood sugar(HbA1c) is a major risk factor for kidney disease even in the absence of Albuminuria and Retinopathy. Atherosclerosis Risk in Communities (ARIC) Study .

Diabetic nephropathy is the leading cause of kidney failure in the United States. The extent to which an elevated glycated haemoglobin (HbA1c) concentration is associated with increased risk of chronic kidney disease (CKD) in the absence of albuminuria and retinopathy, the hallmarks of diabetic nephropathy, is uncertain.Nearly 1900 adults with diabetes underwent hemoglobin A1c measurements and then were followed for roughly 11 years, during which one fifth developed chronic kidney disease. After adjustment for cardiovascular and other risk factors, the odds of kidney disease rose significantly with increasing HbA1c concentration. For example, compared with HbA1c less than 6%, a concentration of 7%-8% conferred a 2.5-fold increase in risk, and a concentration of over 8%, a 3.7-fold increase.HbA1c remained positively associated with kidney disease even among patients without albuminuria or retinopathy.

The authors conclude: "These data suggest that glycemic control is an important modifiable risk factor in the pathology of kidney disease in individuals with [diabetes], both in the presence and absence of other microvascular damage." Read more........