Comparison of Various Indices in Identifying Insulin Resistance and Diabetes in Chronic Spinal Cord Injury

The purpose of this screening and diagnostic study was to examine the accord among indices of glucose metabolism, including the Homeostatic Model Assessment for Insulin Resistance (HOMA), HOMA2, Matsuda Index, Quantitative Insulin-sensitivity Check Index (QUICKI), hemoglobin A1C (HbA1C), and fasting plasma glucose (FPG) against intravenous glucose tolerance test-measured insulin sensitivity (Si) in individuals with chronic motor complete SCI. Persons with chronic (≥12-months post-injury) SCI (n = 29; 79% men; age 42.2 ± 11.4; body mass index 28.6 ± 6.4 kg/m(2); C4-T10) were included. Measures were compared using adjusted R(2) from linear regression models with Akaike information criterion (AIC, a measure of error). QUICKI had the greatest agreement with Si (adjusted R(2) = 0.463, AIC = 91.1, p = 0.0001), followed by HOMA (adjusted R(2) = 0.378, AIC = 95.4, p = 0.0008), HOMA2 (adjusted R(2) = 0.256, AIC = 99.7, p = 0.0030), and the Matsuda Index (adjusted R(2) = 0.356, AIC = 95.5, p = 0.0004). FPG (adjusted R(2) = 0.056, AIC = 107.5, p = 0.1799) and HbA1C (adjusted R(2) = 0.1, AIC = 106.1, p = 0.0975) had poor agreement with Si. While HbA1C and FPG are commonly used for evaluating disorders of glucose metabolism, QUICKI demonstrates the best accord with Si compared to the other measures.