Renal function in noninsulin-dependent diabetes mellitus patients treated with angiotensin-converting enzyme inhibitors and calcium channel blockers

BACKGROUND: Data have not shown consistent effects with calcium channel blockers on the course of renal function in patients with noninsulin-dependent diabetes mellitus (NIDDM) who have hypertension alone or in association with renal damage. The differences between the antiproteinuric effects of subclasses or formulations of calcium channel blockers and the heterogeneity of renal lesions may contribute to the discrepancy in these data. Clinical studies conducted by the authors and other recent data that describe the course of renal dysfunction in hypertensive NIDDM patients treated with antihypertensive agents are reviewed. Renal structural changes were also evaluated. RESULTS: Most available data indicate that angiotensin-converting enzyme inhibitors and dihydropyridine and nondihydropyridine calcium channel blockers produce similar effects on glomerular filtration rate. In one study of patients achieving intensified, strict control of blood pressure (target<140/85 mmHg) with either cilazapril or amlodipine, glomerular filtration rate declined by 2.03+/-0.66 ml/ min/1.73 m2 per year and 2.01+/-0.71 ml/min/1.73 m2 per year, respectively, in the subgroup with normoalbuminuria and by 2.15+/-0.69 ml/min/1.73 m2 per year and 2.33+/-0.83 ml/min/ 1.73 m2 per year, respectively, in the subgroup with microalbuminuria. Renal lesions in NIDDM patients were found to be structurally heterogeneous and glomerular filtration rate appeared to decline only in patients with renal structural changes typical of NIDDM. CONCLUSIONS: The extent of blood pressure control, rather than the method by which this is accomplished, is the most important factor in determining the evolution of incipient nephropathy in hypertensive NIDDM. The kidneys of microalbuminuric NIDDM patients are structurally heterogeneous with less than one-third of patients having 'typical' diabetic nephropathology.