To the Editor.
—Two placebo-controlled trials have been recently published1,2 that were designed to determine whether captopril has specific kidney-protecting properties in patients with diabetic nephropathy. However, the authors of the studies decided to compare 50 mg1 or 75 mg2 of captopril with placebo and not with another antihypertensive agent. Hence, both study protocols resulted in different blood pressure control between the intervention and the control groups. The significant difference in blood pressure values is discussed in the article by Dr Viberti and colleagues.1 The final results of the study by Lewis et al were presented during the recent 53rd American Diabetes Association meeting in Las Vegas, Nev.3 In that report, the mean (±SD) arterial pressure over all follow-up visits was 96.2±7.9 mm Hg in the captopril group and 100.6±8.9 mm Hg in the placebo group (P=.008).3In previous reports,4,5 a decrease