Effects of antihypertensive drugs on renal function in patients with diabetic nephropathy

Hypertension occurs about twice as frequently in diabetics as in the general population, with a prevalence of approximately 25% in young patients with insulin-dependent diabetes mellitus (IDDM) and 50% in patients with newly diagnosed non-insulin-dependent diabetes mellitus (NIDDM). Studies strongly suggest that hypertension is involved in the progression and perhaps the onset of diabetic nephropathy, which is a major cause of illness and premature death in diabetic patients, largely through accompanying cardiovascular disease and end-stage renal failure. A large body of evidence has accumulated that emphasizes the beneficial effects of antihypertensive treatment in reducing proteinuria and preserving renal function in both IDDM and NIDDM. It appeared that angiotensin converting enzyme inhibitors and certain calcium antagonists, notably nondihydropyridine, calcium antagonists, and second-generation dihydropyridine calcium antagonists, produce a more beneficial effect on nephropathy in terms of reducing proteinuria and slowing progression to renal failure. These drugs are attributed nephroprotective capacity beyond their systemic blood pressure lowering effects, and initial clinical trials with combinations have revealed additive effects on reduction in albuminuria and have led to the lowest rate of decline in glomerular filtration rates with the lowest incidence of adverse effects.