Renal protection in diabetes: lessons from ONTARGET(®)

Hypertension is an important independent risk factor for renal disease. If hypertension and chronic renal disease co-exist, as is common in patients with diabetes mellitus, the risk of cardiovascular disease is heightened. The importance of rigorous blood pressure control is recognized in current guidelines, with a recommended target of office blood pressure of < 130/80 mmHg; although ambulatory blood pressure may be more appropriate in order to identify the 24-hour hypertensive burden. Even lower blood pressure may further reduce the progression of chronic kidney disease, but the incidence of cardiovascular events may increase. Albuminuria not only indicates renal damage, but is also a powerful predictor of cardiovascular morbidity and mortality at least in patients with high cardiovascular risk and potentially pre-existing vascular damage. Management of the multiple factors for renal and cardiovascular disease is mandatory in the diabetic patient. The renin-angiotensin system (RAS) plays a pivotal role in the progression of renal disease, as well as in hypertension and target-organ damage. The use of agents that target the RAS confer renoprotection in addition to antihypertensive activity. There is extensive evidence of the renoprotective effect of angiotensin II receptor blockers (ARBs), and specifically telmisartan. In addition to providing 24-hour blood pressure control, clinical studies in patients with diabetes show that telmisartan improves renal endothelial function, prevents progression from microalbuminuria to macroalbuminuria, slows the decline in glomerular filtration rate and reduces proteinuria in overt nephropathy. These effects cannot be solely attributed to blood pressure control. In contrast to other members of the ARB class, the renoprotective effect of telmisartan is not confined to the management of diabetic nephropathy; slowing the progression of albuminuria has been demonstrated in the ONgoing Telmisartan Alone and in combination with Ramipril Global Endpoint Trial (ONTARGET(®)), which included diabetic and non-diabetic patients at high risk of cardiovascular events.