Treatment of diabetic nephropathy in its early stages

Diabetic nephropathy is one of the most frequent causes of end-stage renal disease (ESRD), and, in recent years, the number of diabetic patients entering renal replacement therapy has dramatically increased. The magnitude of the problem has led to numerous efforts to identify preventive and therapeutic strategies. In normoalbuminuric patients, optimal glycemic control (HbA(1c) lower than 7.5%) plays a fundamental role in the primary prevention of ESRD [weighted mean relative risk reduction (RRR) approximately 37% for metabolic control versus trivial renoprotection for intensive anti-hypertensive therapy or ACE-inhibitors (ACE-I)]. In the microalbuminuric stage, strict glycemic control probably reduces the incidence of overt nephropathy (weighted mean RRR approximately 50%), while blood pressure levels below 130/80 mmHg are recommended according to the average blood pressure levels obtained in various studies. In normotensive patients, ACE-I markedly reduce the development of overt nephropathy almost regardless of blood pressure levels; in hypertensive patients, ACE-I are less clearly active (weighted mean RRR approximately 23% versus other drugs), whereas angiotensin-receptor blockers (ARB) appear strikingly renoprotective. Once overt proteinuria appears, it is uncertain whether glycemic control affects the progression of nephropathy. In type 1 diabetes, various anti-hypertensive treatments, mainly ACE-I, are effective in slowing down the progression of nephropathy; in type 2 diabetes, two recent studies demonstrate that ARB are superior to conventional therapy or calcium channel blockers (CCB). In clinical practice, pharmacological tools are not always used to the best benefit of the patients. Therefore, clinicians and patients need to be educated regarding the renoprotection of drugs inhibiting the renin-angiotensin system (RAS) and the overwhelming importance of achieving target blood pressure.