Prevalence of Insulin Resistance in Type 1 Diabetes Mellitus and Its Correlation with Metabolic Parameters: The Double Trouble.

Objective: The phenotype of type 1 diabetes mellitus has changed over the last few decades. Little attention has been paid to the presence of insulin resistance in individuals with type 1 diabetes mellitus. The appearance of insulin resistance in type 1 diabetes mellitus patients has been labeled as "double diabetes." This phenotype of double diabetes has been seen to have higher rate of microvascular as well as macrovascular complica- tions. The aim of the current study was to estimate the burden of insulin resistance in patients with type 1 diabetes mellitus and its correlation with various metabolic parameters and microvascular complications.

Materials And Methods: It was a cross-sectional study in which a total of 95 type 1 diabetes mellitus patients (children/adolescents (<18 years) and adults ≥18 years) presenting to Endocrinology OPD were screened for the presence of insulin resistance using estimated glucose disposal rate. Estimated glucose disposal rate (mg/kg/min) was calculated as = 21.16- (0.09 ×WC) - (3.407×HTN) - (0.551×HbA1c [%]) where, WC is waist circumference (cm) and HTN is hypertension (1= yes, 0 = no). Based on previous studies, an estimated glucose disposal rate <8 was considered to have the presence of insulin resistance and double diabetes.

Results: Using an estimated glucose disposal rate <8 as the cut-off for the presence of insulin resistance, the overall prevalence was 16.8%. Prevalence was high in adults 12 (29.3%) compared to children/adolescents 4 (7.4%) which was statistically significant [χ2 = 7.95; P = .004]. In comparison of the anthropometric and metabolic parameters in those with an estimated glucose disposal rate <8 versus ≥8, there was a significant statistical difference. Those having an estimated glucose disposal rate <8 had higher age, longer duration of diabetes, and body mass index [P ≤ .05]. Also, they had poor glycemic control, higher blood pressure, triglycerides, low-density lipoproteins levels. Using Spearman correlation coefficient there was a statistically significant (P < .05) negative correlation between the estimated glucose disposal rate and various anthropo- metric as well as metabolic parameters.

Conclusion: This study shows that with increasing duration of disease, insulin resistance (low estimated glucose disposal rate) could be a serious problem in type 1 diabetes mellitus patients, especially in those who are metabolically unhealthy. As insulin resistance could be a major contributing factor in the onset and progression of various vascular complications, evaluation of the presence of insulin resistance using estimated glucose disposal rate could be useful in recognizing individuals who would benefit the most from preventa- tive strategies.