Insulin resistance is associated with preclinical carotid atherosclerosis in patients with type 1 diabetes

Aim: Although insulin resistance (IR) is a growing trait among type 1 diabetes (T1D) population, its relationship with atherosclerosis has been scarcely studied. We assessed the association between IR indexes and carotid atherosclerosis in T1D, a population at high cardiovascular disease (CVD) risk.

Materials and methods: We evaluated 191 participants with T1D and no prior CVD with at least one of the following criteria: ≥40 years old; diabetic nephropathy; or T1D duration ≥10 years harbouring ≥1 additional CVD risk factor. IR was assessed with the metabolic syndrome (MetS) harmonized definition proposed in 2009 and the estimated glucose disposal rate (eGDR), a T1D-specific IR surrogate marker (lower values indicating higher IR). Standardized carotid ultrasonography was performed, recording intima-media thickness (IMT), plaque presence and maximum height of plaque. Comparisons between patients according to their MetS status as well as concerning eGDR values were performed.

Results: The participants' median age was 47.4 (41.1-53.3) years and diabetes duration 25.7 (21.6-32.5) years. Plaque prevalence was higher in patients with greater IR (49.1%, 29.1% and 20%, P = .001, for any plaque according to decreasing eGDR tertiles). Conversely, no statistically significant higher plaque prevalence was found in participants with MetS. In multivariate analyses (adjusted for general- and T1D-specific risk factors, and statin treatment), MetS was associated with neither IMT nor plaque. On the contrary, eGDR was independently related to ≥2 plaques (P = .018) and maximum plaque height (P < .01).

Conclusions: In T1D, IR assessed through eGDR but not by MetS definition was independently associated with plaque burden, a predictor of CVD.