Effect of intensive blood pressure control on the course of type 1 diabetic nephropathy

Diabetic nephropathy is the most common cause of end-stage renal disease in the United States. We undertook a study to assess the impact of assignment to different levels of blood pressure control on the course of type 1 diab etic nephropathy in patients receiving angiotensin converting enzyme (ACE) inhibitor therapy, We also examined the long-term course of this well-chara cterized cohort of patients receiving ACE inhibitor therapy, One hundred tw enty-nine patients with type 1 diabetes and diabetic nephropathy who had pr eviously participated in the Angiotensin-Converting Enzyme Inhibition in Di abetic Nephropathy Study who had a serum creatinine level less than 4.0 mg/ dL were randomly assigned to a mean arterial blood pressure (MAP) goal of 9 2 mm Hg or less (group I) or inn to 107 mm Hg (group II). Patients received varying doses of ramipril as the primary therapeutic antihypertensive agen t, All patients were followed for a minimum of 2 years. Outcome measures in cluded iothalamate clearance, 24-hour creatinine clearance, creatinine clea rance estimated by the Cockcroft and Gault formula, and urinary protein exc retion, The average difference in MAP between groups was 6 mm Hg over the 2 4-month follow-up. The median iothalamate clearance in group I was 62 mL/mi n/1.73 m(2) at baseline and 54 mL/min/1.73 m(2) at the end of the study com pared with a baseline of 64 mL/min/1.73 m(2) and final 58 mL/min/1.73 m(2) in group II. There were no statistically significant differences in the rat e of decline in renal function between groups. There was a significant diff erence in follow-up total urinary protein excretion between group I (535 mg /24 h) and group II (1,723 mg/24 h; P = 0.02), Thirty-two percent of 126 pa tients achieved a final total protein excretion less than 500 mg/24 h, Pati ents from groups I and II had equivalent rates of adverse events, In patien ts with type 1 diabetes mellitus and diabetic nephropathy, the MAP goal sho uld be 92 mm Hg or less for optimal renoprotection, if defined as including decreased proteinuria. With the combination of ACE inhibition and intensiv e blood pressure control, many patients can achieve regression or apparent remission of clinical evidence of diabetic nephropathy. (C) 1999 by the Nat ional Kidney Foundation, Inc.