This page should have been published last week as Vol 264 No 7085
Intensive therapy for patients with diabetes mellitus should be implemented "as early as is safely possible" and be maintained for "as long as possible", a new trial has shown. The Epidemiology of Diabetes Intervention and Complications (EDIC) trial was a follow-up to the Diabetes Control and Complications trial (DCCT), a US trial published in 1993, which concluded that the risk of developing microvascular complications of diabetes was reduced by intensive therapy designed to achieve near-normal blood glucose levels.
Following, the DCCT, all trial participants were offered intensive therapy under the care of their own general practitioner. Most were then enrolled in the EDIC trial, a four year, observational study to assess whether the benefits of intensive therapy seen in the DCCT, which had an average treatment period of 6.5 years, were maintained.
The EDIC authors report that "the reduction in the risk of progressive retinopathy and nephropathy resulting from intensive therapy in patients with type 1 diabetes persists for at least four years." These results were seen despite increasing levels of hyperglycaemia. At the end of the DCCT, the incidence of hyperglycaemia was lower in the intensive group but by the end of the EDIC study, the levels had converged to a figure between the two.
However, the long-term outcomes were still improved. The rate of prevalence of various levels of retinopathy was significantly lower. After four years, 21 per cent of the 581 patients in the original conventional therapy group compared with 6 per cent of the 596 patients in the intensive therapy group had progression of retinopathy.
For renal outcomes, microalbuminuria was detected for the first time in 11 per cent of 573 conventionally treated patients and 5 per cent of 601 patients in the former intensive therapy group.
These findings have led the trial's authors to suggest that maintaining "near-normal glycosylated haemoglobin concentrations has a beneficial effect on the long-term complications of diabetes that persists long after the actual period of treatment" (New England Journal of Medicine 2000;342:381).