Etiology, diagnosis, and prevention of renal involvement in insulin-dependent diabetes mellitus

Overt diabetic nephropathy is a well-established clinical picture characterized by macroproteinuria and irreversible decline of glomerular function. The first phase of renal involvement has been widely investigated in the last decade in the hope to individuate early lesions. Five stages of glomerular damage have been identified by morphological abnormalities and clinical tests. Although renal hypertrophy, hyperfiltration, and microalbuminuria are present in all diabetics at onset, subsequent evolution shows different patterns: some patients may present no further progression, while others show a rapid and irreversible decline of kidney function. This suggests that other factors, i.e., risk factors, may play important roles in the renal involvement in diabetics. The predictive role of microalbuminuria and of hyperfiltration was investigated, and, so far, only an albumin excretion rate above 30 micrograms/min had been proved to be associated with a decline of renal function. Actually no practical hints can be given to prevent the disease apart from persistent strict glycometabolic control during the course of diabetes. Antihypertensive treatment can slow glomerular damage when overt diabetic nephropathy and hypertension are present. Aggressive treatment in the early phases of renal involvement might change the natural history of the disease.