Concerns about diabetic nephropathy in the treatment of diabetic hypertensive patients

Diabetic nephropathy ultimately develops in approximately, 40 percent of patients with insulin-dependent diabetes mellitus, as well as in a significant fraction of those with non-insulin-dependent diabetes. Consequently, diabetic nephropathy represents the most common single cause of end-stage renal failure in adults. Recent studies indicate that the subset of insulin-dependent diabetic patients who develop nephropathy may have a genetic susceptibility to renal injury resulting from the abnormal physiologic milieu associated with diabetes. This is perhaps due to abnormal glomerular hemodynamic responses resulting in glomerular capillary hypertension. Diabetic nephropathy progresses through a prolonged subclinical stage characterized by abnormal urinary albumin excretion rates (30 to 250 mg/24 hours, "microalbuminuria") and small, but significant, increases in arterial blood pressure. This stage of incipient diabetic nephropathy represents the earliest point at which patients destined to develop overt diabetic nephropathy (albumin excretion rate of more than 250 mg/24 hours, hypertension, and decreased glomerular filtration rate) can be identified, and targets a population that may benefit from therapy aimed at preventing progression of renal failure. Hypertension is intimately related to the development and progression of diabetic nephropathy. Control of hypertension has been clearly shown to slow or arrest the progression of diabetic nephropathy and represents the most important therapeutic option available. Preliminary studies suggest that treatment consisting of strict metabolic control and selective antihypertensive agents during the stage of incipient nephropathy could potentially prevent the development of overt nephropathy. Although control of hypertension with any regimen is most likely beneficial, those agents endowed with selective protective effects on the glomerulus may confer optimal preservation of renal function. Patients with diabetes mellitus, whether insulin-dependent or non-insulin-dependent, are at increased risk for developing systemic arterial hypertension. The treatment of hypertension in diabetic patients takes on importance beyond the usual concerns for reducing blood pressure in other hypertensive patients. In diabetic patients, hypertension is directly linked to the development and progression of nephropathy. If this devastating complication is to be minimized or prevented, then control of arterial hypertension must be a major goal of therapy from the earliest stages of the disease process.