Homeostatic Insulin Sensitivity Indices Is the Detection of Gestational Diabetes Mellitus

Abstract

Background: Early identification of GDM is strongly warranted for prevention of both maternal and fetal complications, but well known disadvantages of the present methods based on oral glucose challenge reduces the compliance and applicability of these methods in the screening of the disorder. Aims: The study aimed to assess FBG-based insulin sensitivity indices (ISIs) regarding their suitability as alternatives of 2 hr 75-g OGTT. Methods and Materials: Out of 300 subjects, 112 had GDM. Finally 84 GDM and 82 normal mothers were analyzed. A nested case control study was conducted with group of pregnant mothers, at 24 to 32 weeks of gestation, were recruited from BIRDEM (the tertiary hospital of Diabetic Association of Bangladesh) was screened for GDM by adapting WHO criteria. Serum glucose and insulin was measured by glucose oxidase and chemluminescence based ELISA. (ISIs) as well as glycemic and insulinemic indices were calculated their ability to detect GDM. Homeostatic formulas were used to quantify insulin sensitivity and B-cell function. McNamara test was used to calculate sensitivity, specificity, PPV and NPV of various tests against the gold standard of OGTT. Results: HOMA%B was significantly (p<0.001) lower in GDM (113.3±51.4) than their non-GDM counterparts (207.9±91.3). In Pearson’s correlation, HOMA%B had a significant correlation with age, FBG, 75-g OGTT and fasting insulin level. HOMA%S showed significantly correlation with FBG, 75-g OGTT, fasting insulin, HOMA%B and QUICKI. Logistic regression provided significant association of HOMA%B with GDM (p=0.002) after adjusting the effect of the confounders. The value of different screening markers for predicting GDM was explored. HOMA%S at optimum cut-off value of 50 showed sensitivity of 50% and specificity of 56%, with PPV and NPV 56% and 55% respectively. QUICKI had 28% and 31% respectively at an optimum cut-off value of 0.54. Fasting insulin showed 54% and 49% respectively at cut-off value of 12.9µU/ml with PPV 50% and NPV 50%. At an optimum cut- off value of 5mmol/l, the sensitivity, specificity, PPV and NPV of FBG was 82%, 78%, 79% and 81% respectively The corresponding value for combined fasting glucose and fasting insulin were 84%, 79%, 82% and 82%.Conclusion: The data suggest that (ISIs), such as simple fasting blood glucose with a cut-off value of 5.0mmol/l, for Bangladeshi population, seems to be an acceptable test in the detection of GDM.