Important new results on intensive glycemic

Over the last few years, the medical community has become increasingly convinced that effective glycemic control can ameliorate the course of microvascular lesions in patients with type 1 and 2 diabetes, especially with respect to retinopathy and nephropathy. Important new follow-up results are now available, from the DCCT and the Kumamato study (1,2).

DCCT
    The DCCT study has been reexamined, 4 years after the end of the trial, to assess whether the benefits on microvascular lesions, in terms of the occurrence of severity of retinopathy and nephropathy, persist in the long term (1). A total of 1208 patientes were followed up 4 years after the DCCT, and nephropathy was evaluated on basis of urine specimens obtained in the 3rd and 4th years. Retinopathy was also evaluated by fundus photography. After the original trial was over, the mean HbA1c increased in the intensively treated group and decreased somewhat in the less intensively treated group, so that there was a narrowing in the difference to 8.2 versus 7.9%, respectively, which is still significant.

    Nevertheless, the worsening of retinopathy was reduced in the intensively treated group, as was the case for renal abnormalities. The proportion of patients with an increase in urine albumine excretion was significantly lower in the intensively treated group. Importantly, the study also confirmed that microalbuminuria is a strong predictor of overt proteinuria during standard insulin treatment. The conclusion is clear: the progression of nephropathy and retinopathy can be reduced by intensive therapy, and the beneficial effects seem to persist.

Kumamoto
    A similar approach was used by the Japanese investigators in the Kumamoto study (2), where the goal was to determine whether intensive glycemic control would lower the frequency of severe microvascular complications. This involved an 8-year follow-up in patients with type 2 diabetes treated with conventional insulin injections (CIT) and multiple insulin injections (MIT). The cumulation percentage of worsening of retinopathy and nephropathy was significantly lower in the intensively treated group, although the difference was not pronounced. Indeed, nephrological changes has progressed to a lesser extent in the intensive treatment group.

    Thus, in insulin-treated type 2 diabetic patientes in Japan, too, intensive glycemic control over many years can delay the onset and progression of the early stages of microvascular lesions. It would be interesting to see further follow-up from the UKPDS, in which retinopathy was reduced by intensive treatmen. More results regardingrenal abnormalities are needed and awaited.

C.E. Mogensen
Aarhus, Denmark.

References:
1. The Diabetic Control and Complications Trial and the Epidemiology of Diabetes Intervention and Complication Research Group. N Engl J Med 2000;342:381-389.
2. Shichiri M, Kishikawa H, Ohkubo Y, Wake N. Diabetes Care 2000;23(suppl):B21-B29.

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