Evidence-based guide to slowing the progression of early renal insufficiency : Slowing early renal insufficiency

Microalbuminuria and hypertension are risk factors for diabetic nephropathy. Blockade of the renin-angiotensin system slows the progression to diabetic nephropathy in patients with type 1 diabetes, but similar data are lacking for hypertensive patients with type 2 diabetes. We evaluated the renoprotective effect of the angiotensin-II-receptor antagonist irbesartan in hypertensive patients with type 2 diabetes and microalbuminuria. A total of 590 hypertensive patients with type 2 diabetes and microalbuminuria were enrolled in this multinational, randomized, double-blind, placebo-controlled study of irbesartan, at a dose of either 150 mg daily or 300 mg daily, and were followed for two years. The primary outcome was the time to the onset of diabetic nephropathy, defined by persistent albuminuria in overnight specimens, with a urinary albumin excretion rate that was greater than 200 microg per minute and at least 30 percent higher than the base-line level. The base-line characteristics in the three groups were similar. Ten of the 194 patients in the 300-mg group (5.2 percent) and 19 of the 195 patients in the 150-mg group (9.7 percent) reached the primary end point, as compared with 30 of the 201 patients in the placebo group (14.9 percent) (hazard ratios, 0.30 [95 percent confidence interval, 0.14 to 0.61; P< 0.001] and 0.61 [95 percent confidence interval, 0.34 to 1.08; P=0.081 for the two irbesartan groups, respectively). The average blood pressure during the course of the study was 144/83 mm Hg in the placebo group, 143/83 mm Hg in the 150-mg group, and 141/83 mm Hg in the 300-mg group (P=0.004 for the comparison of systolic blood pressure between the placebo group and the combined irbesartan groups). Serious adverse events were less frequent among the patients treated with irbesartan (P=0.02). Irbesartan is renoprotective independently of its blood-pressure-lowering effect in patients with type 2 diabetes and microalbuminuria.

In type 2 diabetes mellitus the aetiology of long-term complications is multifactorial. We carried out a randomised trial of stepwise intensive treatment or standard treatment of risk factors in patients with microalbuminuria. In this open, parallel trial patients were allocated standard treatment (n=80) or intensive treatment (n=80). Standard treatment followed Danish guidelines. Intensive treatment was a stepwise implementation of behaviour modification, pharmacological therapy targeting hyperglycaemia, hypertension, dyslipidaemia, and microalbuminuria. The primary endpoint was the development of nephropathy (median albumin excretion rate >300 mg per 24 h in at least one of the two-yearly examinations). Secondary endpoints were the incidence or progression of diabetic retinopathy and neuropathy. The mean age was 55.1 years (SD 7.2) and patients were followed up for 3.8 years (0.3). Patients in the intensive group had significantly lower rates of progression to nephropathy (odds ratio 0.27 [95% CI 0-10-0.75]), progression of retinopathy (0.45 [0.21-0.95]), and progression of autonomic neuropathy (0.32 [0.12-0.78]) than those in the standard group. Intensified multifactorial intervention in patients with type 2 diabetes and microalbuminuria slows progression to nephropathy, and progression of retinopathy and autonomic neuropathy. However, further studies are needed to establish the effect of intensified multifactorial treatment on macrovascular complications and mortality.