Single versus dual blockade of the renin-angiotensin system (angiotensin-converting enzyme inhibitors and/or angiotensin II receptor blockers) in diabetic nephropathy

PURPOSE OF REVIEW: Antihypertensive treatment has improved renal prognosis and survival in diabetic nephropathy. The present review summarizes the current status of blockade of the renin-angiotensin system in diabetic nephropathy. Since the current treatment strategies reduce, but do not prevent, the progression of kidney disease, the research focus is directed towards the potential renoprotective effects of dual blockade of the renin-angiotensin system using both angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers. RECENT FINDINGS: Angiotensin-converting enzyme inhibitors are now a first-line therapy for patients with type 1 diabetes and diabetic nephropathy, whereas in patients with type 2 diabetes, angiotensin II receptor blockers have been shown to protect the kidney. The optimal doses of both types of drug remain to be determined, and the efficacy of each medication needs to be compared both in patients with type 1 diabetes and in those with type 2 diabetes. Experimental studies suggests that dual blockade of the renin-angiotensin system may offer additive beneficial effects relative to angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers. In agreement with this, short-term studies of patients with diabetes have suggested that further renal and cardiovascular protection is achieved using dual blockade of the renin-angiotensin system. Long-term trials will finally define the role of this new treatment concept in diabetic nephropathy. SUMMARY: All diabetic patients with elevated urinary albumin excretion need blockade of the renin-angiotensin system by either angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers. In addition, albuminuria and elevated blood pressure should be treated aggressively with a view to achieving blood pressure readings below 130/80 mmHg and albuminuria values of less than 300 mg/24 h; this often necessitates multi-pharmacy. Dual blockade of the renin-angiotensin system may be helpful in reaching these goals in treatment-resistant patients with diabetic nephropathy.