The Diabetes Control and Complications Trial (DCCT) has documented the profound beneficial effects of intensive diabetes therapy (INT) compared with conventional therapy (CON) on the development and progression of microvascular and neuropathic complications during the DCCT, mediated by the separation of HbA1c levels between the two treatment groups. In addition, the further separation of these outcomes during the Epidemiology of Diabetes Interventions and Complications (EDIC) study, despite the disappearance of the differences in HbA1c seen in the DCCT (metabolic memory), has been described. The long-term benefits of INT versus CON are almost completely explained by the differences between the two groups in the mean level of HbA1c during the mean of 6.5 years of treatment in the DCCT .
They assessed carotid IMT by ultrasonography at EDIC years 1, 6, and 12 . At year 1, the results were largely within the age-matched, nondiabetic range with no difference between the DCCT INT and CON groups. Carotid ultrasonography was again repeated during EDIC year 6. During the ∼5 year period between the two measurements, IMT increased within both groups, significantly more so in the former CON than INT group (Fig. 1). Ultrasonography was again conducted during year 12 (12). IMT increased even more in both groups, consistent with the recognized effects of aging. The magnitude of the increase between EDIC years 6 and 12 was slightly greater in the former INT than in the CON group, but the mean IMT remained significantly less at 12 years in the former INT group.
