EFFECT OF TWO YEARS OF STRICT METABOLIC CONTROL ON PROGRESSION OF INCIPIENT NEPHROPATHY IN INSULIN-DEPENDENT DIABETES

Abstract

36 patients with insulin-dependent diabetes mellitus who had 'Albustix'-negative urine but raised urinary albumin excretion (30 to 300 mg/24 h) were randomly assigned to either remaining on conventional insulin treatment or continuous subcutaneous insulin infusion and followed up for 2 years. The insulin-infusion group showed a significant, sustained improvement in metabolic control, with a median glycosylated haemoglobin of 7.2% (range 5.9-8.8), but there was no change in the conventional-treatment group (median 8.6%, range 7.2-13.4) (p<0.001). Clinical diabetic nephropathy (a urinary albumin excretion rate above 300 mg/24 h in at least two of three 24 h urine collections) developed in 5 patients in the conventional-treatment group, but not in the insulin-infusion group (p<0.05, two-tailed). Fractional albumin clearance (mean and range × 10 7) increased in the conventional-treatment group from 160 (35-468) to 360 (29-1580) and was unchanged in the insulin-infusion group (170 [31-608] before to 160 [26-460] after) (p<0.05). Insulin infusion had an overall beneficial effect on the annual increase in urinaryb albumin excretion (p<0.05), and the mean glycosylated haemoglobin values correlated positively with annual change in albumin excretion (r=0.57, p<0.0001). The diastolic, blood pressure rose significantly in the conventional-treatment group (p<0.001), and annual change in mean blood pressure correlated with change in urinary albumin excretion (r=0.49, p<0.001).