Estimation of reference intervals of insulin resistance (HOMA), insulin sensitivity (Matsuda), and insulin secretion sensitivity indices (ISSI-2) in Polish young people

Introduction. Insulin resistance is becoming an increasingly widespread problem worldwide. For its determination indirect indices of insulin resistance or insulin sensitivity have used. Those indices based on simultaneous measurements of blood glucose and insulin concentrations under fasting conditions or during the Oral Glucose Tolerance Test. Objective. The aim of the study was to estimate reliable reference values for the indices used in insulin resistance diagnosis. Materials and method. 191 selected participants, aged 18-31, were enrolled into the reference population. 130 participants from the reference population with fasting glucose <= 5.5 mmol/L, BMI<25 kg/m(2), and without metabolic syndrome, were finally included in the reference group. The following insulin resistance indices were calculated: HOMA1-IR, HOMA2, HOMA2 from C-peptide, QUICKI, Matsuda Index and Insulin Secretion-Sensitive Index-2. Determination of reference intervals for indirect indices of insulin resistance was conducted in accordance with the C28-A3 procedure recommended by the Clinical & Laboratory Standards Institute (CLSI). Results. The reference intervals for indirect insulin resistance indices examined according to CLSI protocol were: <= 4.00, <= 2.27, <= 4.10, >= 0.31 for HOMA1-IR, HOMA2, HOMA2 C-pep., and QUICKI, respectively. For insulin sensitivity, the value of the Matsuda Index was established as >= 3.19 and for beta cell pancreatic function ISSI-2 as >= 206. Conclusions. Establishing a reference intervals for these indices enable the proper identification and differentiation of the types of insulin resistance in particular populations. The early detection of metabolic disorders allows for introduction of effective preventive action.