Insulin resistance and associated factors in patients with Type 1 Diabetes

OBJECTIVE To assess the presence of insulin resistance (IR) in patients with type 1 diabetes (T1DM) according to the estimated glucose disposal rate formula (eGDR) and the insulin sensitivity score (ISS) and to estimate the correlation between these two measures and identify the clinical and laboratory markers related to IR. RESEARCH DESIGN AND METHODS Cross-sectional study of adults with T1DM (n = 135). The results of the formulas that estimate IR were separated into quartiles and correlated with demographic data, clinical characteristics and laboratory parameters. We analyzed the total and regional adiposity by dual-energy X-ray absorptiometry and skin fold thickness measurements. RESULTS Two thirds of the patients were overweight or obese. A moderate correlation was found between eGDR and ISS (r = 0.612). The results of both formulas were positively correlated with BMI (r = -0.373 eGDR and r = -0.721 ISS), thoracic-abdominal fat (r = -0.484 eGDR and r = -0.758 ISS), waist/height ratio (r = -0.537 eGDR and r = -0.779 ISS), subscapular skinfold (mm) (r = -0.356 eGDR and r = -0.569 ISS), total dose insulin IU/lean mass (kg) (r = -0.279 eGDR and r = -0.398 ISS), age (years) (r = -0.495 eGDR and r = -0.190 ISS) and diabetes duration (years) (r = -0.428 eGDR and r = -0.187 ISS). A moderate agreement (Kappa 0.226) was observed between the 1st quartile of results determined by the formulas in 10.4% of the patients, but the 4th quartile presented a strong correlation (Kappa 0.679). The individuals with IR that were classified in the 1st quartile by the ISS formula had a higher chance of presenting with acanthosis nigricans (OR = 5.58, 95% CI =1.46-21.3). CONCLUSIONS The correlations found in this study indicate the possibility of using clinical and laboratory data to estimate IR in patients with TDM1. The detection of IR in T1DM patients may allow early intervention and possibly impact on future diabetes complications.