Absence of albuminuria in type 2 diabetics with classical diabetic nephropathy: Clinical pathological study

Abstract

Background: Diabetic nephropathy is the most common cause of chronic kidney disease and the number afflicted patients continues to rise. The presence of proteinuria has been considered as a prerequisite for the diagnosis of diabetic nephropathy. But one third to one half of type 2 diabetics with CKD have no proteinuria and the pathology of non proteinuric CKD in this group remains unclear as renal biopsy is commonly not performed in these patients. The present study addresses the question: Can a classical diabetic nephropathy occur in the absence of proteinuria? Method: We examined renal biopsies of subjects who underwent nephrectomy from 1999 to 2009 for renal cancer, had eGFR < 60 ml/min and no microalbuminuria or proteinuria. 10 diabetics were matched with 10 non diabetics for age, hypertension and baseline creatinine. Results: The diabetic subjects had advanced diabetic lesions even in absence of proteinuria. Tubules and tubular-interstitium was relatively well preserved. Diabetic glomerulosclerosis can occur in the absence of microalbuminuria. Conclusions: It is becoming increasingly apparent that a considerable proportion of subjects with type 2 diabetes can develop renal impairment in the absence of albuminuria. Diabetic glomerulosclerosis may develop before the proteinuria can be detected and relying on albumin excretion as first sign for renal involvement may be too late in diagnosing and modifying the progression of the kidney disease.