Telmisartan in incipient and overt diabetic renal disease

Background: Renal dysfunction can be regarded as a continuum that extends from endothelial dysfunction to microalbuminuria, macroalbuminuria, end-stage renal disease and ultimately to death. All stages of this continuum are associated with progressively increasing cardiovascular risk. Preventing the development and progression of kidney disease requires rigorous management of blood pressure. Due to the important role of the renin-angiotensin system in the pathogenesis of diabetic renal disease, agents that inhibit this system are recognized as first-line therapy, offering both effective blood pressure lowering and direct actions on the kidney. This review examines the effects of the angiotensin II receptor blocker telmisartan on renal dysfunction. Methods: Renal studies with telmisartan were obtained from a search on Medline and from the authors' literature sources. Results: Telmisartan provides renal benefit at all stages of the renal continuum in patients with type 2 diabetes. It improves endothelial function in patients with normoal-buminuria, delays the progression to overt nephropathy in patients with microalbuminuria and reduces proteinuria in patients with macroalbuminuria. Effectiveness of telmisartan is comparable to angiotensin-converting enzyme inhibitors, but with greater tolerability. The effect of telmisartan on protein excretion in diabetic nephropathy appears to be better than that of losartan and equivalent to that of valsartan. In the ONTARGET study, telmisartan provided similar cardiovascular protection to ramipril in a broad at-risk population that included patients with diabetes, while being better tolerated and having fewer treatment discontinuations. Conclusion: The effects of telmisartan on kidney function support its use in patients with microalbuminuria or overt diabetic nephropathy.