Hypertension and kidney disease of diabetes mellitus

Kidney disease is a primary cause of morbidity and mortality in diabetic patients. Factors that predetermine development of nephropathy remain unknown. Poor glycemic control, insulin requirement, duration of diabetes and family history of hypertension appear to be associated with an increased risk. Arterial hypertension, which is twice as common in diabetic patients as in the normal population, accelerates the progression of diabetic nephropathy. The pathophysiologic mechanisms responsible for hypertension appear to be different in IDDM and NIDDM. In IDDM, hypertension occurs usually as a consequence of diabetic renal disease. Conversely, the pathogenesis in NIDDM appears to be multifactorial. In either condition, aggressive blood pressure control is the single most important intervention proven to retard the progression of nephropathy. A stepped-care approach similar to that for essential hypertension with slight modifications is indicated in the treatment of the hypertensive diabetic patient with nephropathy. Nonpharmacological therapy, including dietary protein restriction, should be used as first step. Selection of the ideal antihypertensive must be based not only on efficacy but also on its side effect profile. Angiotensin converting enzyme inhibitors and calcium antagonists have a low incidence of side effects and do not induce metabolic disturbances. Therefore, they are the agents of choice for patients who do not respond to nonpharmacological therapy alone. Thiazide diuretics and beta-blockers should be used as first line therapy only for specific indications. Antihypertensive therapy combined with good glycemic control and dietary protein restriction constitute the standard of care for diabetic patients with hypertension and renal disease.