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 less than 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 less than 0.01]. The change in urinary albumin excretion was associated with the glycaemic control (n = 69, r = 0.49, p less than 0.0002). No progression was observed among 32 patients with low range microalbuminuria (30 to 99 mg/24 h).(ABSTRACT TRUNCATED AT 250 WORDS)