Diabetes
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Multicenter Study Comparative Study Clinical Trial Controlled Clinical Trial
The relationship of glycemic exposure (HbA1c) to the risk of development and progression of retinopathy in the diabetes control and complications trial.
The Diabetes Control and Complications Trial (DCCT) demonstrated that a regimen of intensive therapy aimed at maintaining near-normal blood glucose values markedly reduces the risks of development or progression of retinopathy and other complications of insulin-dependent diabetes mellitus (IDDM) when compared with a conventional treatment regimen. This report presents an epidemiological assessment of the association between levels of glycemic exposure (HbA1c) before and during the DCCT with the risk of retinopathy progression within each treatment group. The initial level of HbA1c observed at eligibility screening as an index of pre-DCCT glycemia and the duration of IDDM on entry were the dominant baseline predictors of the risk of progression. ⋯ When examined simultaneously within each treatment group, each of the components of pre-DCCT glycemic exposure (screening HbA1c value and IDDM duration) and glycemic exposure during the DCCT (mean HbA1c, time in study, and their interaction) were significantly associated with risk of retinopathy progression. Similar results also apply to other retinopathic, nephropathic, and neuropathic outcomes. The recommendation of the DCCT remains that intensive therapy with the goal of achieving near-normal glycemia should be implemented as early as possible in as many IDDM patients as is safely possible.