Effect of blood pressure control on diabetic microvascular complications in patients with hypertension and type 2 diabetes

OBJECTIVE - The Appropriate Blood Pressure Control in Diabetes (ABCD) Trial is a prospective randomized blinded clinical trial that compares che effec ts of intensive versus moderate blood pressure control on the incidence and progression of type 2 diabetic complications. The current article discusse s the results of 5.3 years of follow-up of 470 patients with hypertension a nd evaluates the effects of intensive and moderate blood pressure therapy u sing nisoldipine versus enalapril as the initial antihypertensive medicatio n for nephropathy, retinopathy, and neuropathy. RESEARCH DESIGN AND METHODS - The 470 hypertensive subjects, defined as hav ing a baseline diastolic blood pressure of greater than or equal to 90 mmHg , were randomized to intensive blood pressure control (diastolic blood pres sure goal of 75 mmHg) versus moderate blood pressure control (diastolic blo od pressure goal of 80-89 mmHg). RESULTS - The mean blood pressure achieved was 132/78 mmHg in the intensive group and 138/86 mmHg in the moderate control group. During the 5-year fol low-up period, no difference was observed between intensive versus moderate blood pressure control and those randomized to nisoldipine versus enalapri l with regard to the change in creatinine clearance. After the first year o f antihypertensive treatment, creatinine clearance stabilized in both the i ntensive and moderate blood pressure control groups in those patients with baseline normo- or microalbuminuria. In contrast, patients starting with ov ert albuminuria demonstrated a steady decline in creatinine clearance of 5- 6 ml.min(-1).1.73 m(-2) per year throughout the follow-up period whether th ey were on intensive or moderate therapy. There was also no difference betw een the interventions with regard to individuals progressing from normoalbu minuria to microalbuminuria (25% intensive therapy vs. 18% moderate therapy , P = 0.20) or microalbuminuria to overt albuminuria (16% intensive therapy vs. 23% moderate therapy P = 0.28). Intensive therapy demonstrated a lower overall incidence of deaths, 5.5 vs. 10.7%, P = 0.037. Over a 5-year follo w-up period, there was no difference between the intensive and moderate gro ups with regard to the progression of diabetic retinopathy and neuropathy. In addition, the use of nisoldipine versus enalapril had no differential ef fect on diabetic retinopathy and neuropathy. CONCLUSIONS - Blood pressure control of 138/86 or 132/78 mmHg with either n isoldipine or enalapril as the initial antihypertensive medication appeared to stabilize renal function in hypertensive type 2 diabetic patients witho ut overt albuminuria over a 5-year period. The more intensive blood pressur e control decreased all-cause mortality.