DIABETES - RENAL-FUNCTION - WHAT ARE THE SPECIAL PROBLEMS

Diabetic nephropathy has become the single most important cause of end stage renal failure in most countries of the Western world. Against th is background, the role of the renin-angiotensin system (RAS) and its blockade command considerable interest. In diabetic patients and in di abetic animals, the circulating components of the RAS are suppressed. Although the evidence is not completely uniform, there are indirect ar guments (renal hemodynamic response to RAS blockade, AT(1) receptor ex pression), however, which would be consistent with increased intrarena l action of angiotensin (ANG) II. There is solid evidence that ACE inh ibitors effectively interfere with progression of microalbuminuria bot h in IDDM and NIDDM. They also prevent progression of advanced renal f ailure in IDDM, while there is only preliminary evidence in this respe ct for NIDDM. ACE inhibitors are superior to conventional antihyperten sive agents (with the possible exception of some calcium channel block ers), but such superiority is seen only when the levels of blood press ure are relatively high. In diabetic animals, treatment with ANG IT re ceptor blockers interferes with the development of glomerular lesions. In acute and subacute studies on diabetic patients, ANG II receptor b lockers reduced albuminuria (or proteinuria) more than beta-blockers. Head-on comparison of equipotent doses ACE inhibitors and ANG II recep tor blockers in non-diabetic patients produced equal reductions in pro teinuria. The long-term effects of ANG II receptor blockers on progres sion of advanced diabetic nephropathy is the object of two large inter national studies. The results will not be available before the year 20 00.