When discussing insulin resistance and insulin sensitivity, data from literature focuses on obese and overweight patients. In our study on, 110 patients with normal body-mass index with newly diagnosed type 2 diabetes mellitus, with the help of glucose tolerance test, we explored insulin resistance, sensitivity, early insulin secretion and β-cell function assessed by using the following indexes: HOMA-IR, ISI, IGI and HOMA-β. We compared the results from our reference group with a control group of 109 overweight patients with newly diagnosed type 2 diabetes mellitus. Normal weight patients had a statistically significant lower HOMA-IR index than overweight patients (2.65 vs. 3.55, p<0.01), however in both groups HOMA-IR was above the cut-off value of 2.5. HOMA-β was statistically significant lower in normal weight patients than in overweight patients (55.08 vs 65.36, p<0.01). ISI index was in an inverse proportional relationship with HOMA-IR, statistically significant higher in normal weight individuals (5.97 vs.3.48, p<0.01). IGI index was not statistically significant lower in normal weight patients (3.63 vs.3.95, p=0.07). It is important to observe that although they have a normal BMI these patients are insulin-resistant confirming the hypothesis of metabolic obese normal weight patients that develop type 2 diabetes mellitus. The indexes that correlate with HbA1c in normal weight patients, predicting glucose status, are HOMA-β (negative correlation), ISI (positive correlation) and IGI index (negative correlation).
Keywords: insulin, β-cell, glycated hemoglobin, type 2 diabetes mellitus
Insulin Resistance and β-Cell Function of Lean versus Overweight or Obese Filipino Patients with Newly Diagnosed Type 2 Diabetes Mellitus
