The long-term effects of poorly controlled diabetes are well known and have a significant adverse impact on the quality of life of those affected. One such adverse effect is diabetic nephropathy. Angiotensin converting enzyme (ACE) inhibitors have been shown to have a renoprotective effect in hypertensive patients with diabetes. Although evidence indicates that diabetic nephropathy cannot be cured, persuasive data exist indicating that its clinical course can be modified by tighter control of blood glucose levels, lifestyle modifications and normalization of blood pressure. Ahmad and colleagues conducted a randomized, single-blind, placebo-controlled study to determine the long-term efficacy of enalapril in reducing the progression of microalbuminuria to clinical albuminuria in normotensive patients with type 2 (non–insulin-dependent) diabetes mellitus.

The study included 103 nonobese, normotensive patients with type 2 diabetes who were followed for five years. Patients were randomly assigned to receive either placebo or 10 mg enalapril daily. Albumin excretion, blood pressure, fasting plasma glucose, HbA₁, serum creatinine, and serum and urinary electrolytes in 24-hour urine samples were checked every three to four months. In patients who received enalapril, albumin excretion decreased from a mean of 55 mg per minute at baseline to 20 mg per minute after five years; in the placebo group, albumin excretion increased from a mean of 53 mg per minute at baseline to 85 mg per minute after five years. Within five years, 7.7 percent of enalapril-treated patients and 23.5 percent of placebo-treated patients progressed to clinical albuminuria (defined as albumin excretion rate of greater than 200 mg per minute).

This study corroborates previous evidence of the renoprotective effect of ACE inhibitors in patients with type 2 diabetes and persistent microalbuminuria. The authors conclude that normotensive patients with type 2 diabetes and microalbuminuria experienced a significant reduction in urinary protein excretion that should slow the progression to end-stage renal disease.

editor's note: Physicians should screen patients with diabetes for diabetic nephropathy according to the guidelines published by the American Diabetes Association and prescribe ACE inhibitors for normotensive diabetic patients with type 2 diabetes and microalbuminuria.—j.n.