The Effect of Features of the Metabolic Syndrome on Atherosclerotic Risk in Relatively Long-Surviving Patients with Type 1 Diabetes

Background: Increasing numbers of patients with type 1 diabetes (T1DM) are developing features of the metabolic syndrome. The additional effect of this on the development of atherosclerosis, as inferred by the carotid artery intima media thickness (IMT), has not previously been assessed. The aim of this study was to assess the effect of features of the metabolic syndrome on carotid artery IMT in a cohort of long-surviving patients with T1DM. Methods: Long-surviving patients with T1DM attending the Centre for Diabetes and Endocrinology were assessed regarding their risk factor profile. All underwent measurement of carotid artery IMT. In all, 156 patients who had T1DM for more than 18 years had their carotid artery IMT measured. All had been attending the clinic for over 10 years, and past clinical and laboratory records were available. Results: A total of 37 patients had metabolic syndrome according to the International Diabetes Federation (IDF) definition. Those with metabolic syndrome had a significantly increased carotid artery IMT (P = 0.003) compared to those without the syndrome. There was a significant relationship between the number of features of metabolic syndrome and increased atherosclerotic risk according to the carotid artery IMT (P = 0.01). A significant correlation was found between carotid artery IMT and both waist circumference (P < 0.001) and insulin resistance (P = 0.005). Conclusions: In long-surviving patients with T1DM, those that develop metabolic syndrome are more likely to have thicker carotid artery IMT, and, by inference, be at higher risk of atherosclerosis and possibly cardiovascular disease. A linear relationship was present between both waist circumference and insulin resistance and carotid artery IMT.