EFFECT OF IMPROVED METABOLIC CONTROL ON LOSS OF KIDNEY-FUNCTION IN TYPE-1 (INSULIN-DEPENDENT) DIABETIC-PATIENTS - AN UPDATE OF THE STENO STUDIES

We re-examined 69 of the 70 patients entering the two independent Steno Studies of effects of improved metabolic control on progression of late diabetic complications. They were analysed according to an intent to treat after follow-up for 8 years (Steno Study 1) and 5 years (Steno Study 2). The glycaemic control had improved in the insulin infusion group compared with the conventional treatment group (mean HbA1c) by 2.0 +/- 0.6% vs 0.7 +/- 1.2 in Steno Study 1 and by 1.8 +/- 1.2% vs 0.4 +/- 1.3 (p < 0.01) in Steno Study 2. In the insulin infusion groups three patients had died during episodes of ketoacidosis. These were not caused by malfunction of the insulin infusion pumps. In the conventional treatment groups, three patients suffered five cardiovascular events causing two deaths. From the sixth month of Steno Study 1 the annual change of the glomerular filtration rate was -3.7 (-5.4 to -2.0) ml.min-1. 1.73 m-2 vs -1.0 (-2.1 to -0.1) (conventional vs insulin infusion group, mean (95% confidence interval, p < 0.01). The change in urinary albumin excretion was associated with the glycaemic control (n = 69, r = 0.49, p < 0.0002). No progression was observed among 32 patients with low range microalbuminuria (30 to 99 mg/24 h). Among the 19 patients with an initial albumin excretion between 100 and 300 mg/24 h, progression of complications was more frequent during conventional treatment (n = 10) vs insulin infusion (n = 9): Clinical nephropathy (10 of 10 vs 2 of 9, p < 0.01) and arterial hypertension (7 of 10 vs 1 of 9, p < 0.01). The glomerular filtration rate declined during conventional treatment by -23 (-42 to -4) ml.mm-1. 1.73 m-2 (p < 0.05) but not during insulin infusion (-13 (-31 to 5) NS). These results suggest that patients at risk of nephropathy should be offered near normal glycaemic control in order to preserve their kidney function.