Reproducibility and discrimination of different indices of insulin sensitivity and insulin secretion

Abstract

Aims Insulin sensitivity and insulin secretion can be estimated by multiple indices from fasting blood samples or blood samples obtained during oral glucose tolerance tests. The test-retest reliability of these indices in repeated measurements within the same individuals can strongly vary. Methods We analyzed data of persons without diabetes who underwent two repeated OGTTs. For each measurement pair, we calculated multiple commonly used indices for the assessment of insulin secretion and insulin sensitivity. We then evaluated the coefficient of variation (standard deviation/mean) and discriminant ratio for each index. Results 89 persons underwent two OGTTs with a median interval of 86 days (IQR 64–249). Among indices of insulin sensitivity derived from fasting blood samples, the revised quantitative insulin sensitivity check index had the smallest coefficient of variation (2.8 ± 2.1%) whereas the C-peptide based homeostasis model assessment 2 had the highest discriminant ratio (1.97 (1.65–2.39)). As for insulin sensitivity indices that are based on OGTT, the oral glucose insulin sensitivity index had the smallest coefficient of variation (6.5 ± 5.1%). The highest discriminant ratio was found for the non-esterified fatty acids-based insulin sensitivity index (NEFA-ISI, 2.70 (2.30–3.22)). For the assessment of insulin secretion from fasting variables, the lowest mean coefficient of variation was found for C-peptide based homeostasis model assessment 2 beta with 10.8 ± 8% and the highest discriminant ratio for the C-peptide / Glucose-Ratio (2.18 (1.84–2.63)). Among indices assessing insulin secretion from an OGTT, the lowest coefficient of variation was found for the ratio of the areas under the C-peptide and glucose curves from 0 to 120 minutes with 11.3 ± 9.7%. Conclusion The data reveal large differences in the reproducibility and the discrimination capability of different indices that assess insulin sensitivity or insulin secretion. Our findings can aid the selection of an appropriate index in clinical studies.

Sex differences in central insulin action: Effect of intranasal insulin on neural food cue reactivity in adults with normal weight and overweight

“…Nonetheless, it is known that peripheral insulin sensitivity changes throughout the cycle [ 58 ] and also eating behavior and preferences may change [ 18 ] and should therefore be addressed in further experiments. Furthermore, peripheral insulin sensitivity was not assessed through hyperinsulinemic-euglycemic clamp but estimated with the widely-used Matsuda index from repeated insulin and glucose measurements during an oGTT [ 65 ].…”

Comprehensive validation of fasting-based and oral glucose tolerance test–based indices of insulin secretion against gold standard measures

“…Another possible contributor to a comparably better correlation of short-term insulin/CP assessment during OGTT with gold standard measures could be a diverging influence of insulin clearance over time. 9 …”

“…Another possible contributor to a comparably better correlation of shortterm insulin/CP assessment during OGTT with gold standard measures could be a diverging influence of insulin clearance over time. 9 Parenteral and oral glucose loading leads to the stimulation of glucose with the involvement of various physiological processes. Oral glucose ingestion activates complex mechanisms, including an incretin-related cascade and even the brain 29 that all in concert control insulin release.…”

“…Several indices have been proposed to estimate insulin sensitivity and insulin secretion, based on more readily measurable parameters obtained in the fasting state or after an oral glucose tolerance test (OGTT). 8 Their usefulness is influenced by the degree of correlation with gold standard indicators, by their reproducibility 9 and by their ability to predict diabetes incidence similarly to more complex methods. [10][11][12] Many surrogate methods for insulin sensitivity assessment have been proposed and validated, 10 12 but comprehensive studies to compare insulin secretion measures to gold standard methods are scarce.…”

Insulin sensitivity is associated with the observed variation of de novo lipid synthesis and body composition in finishing pigs

“…A lower oDI cpep indicates a reduced ability for β-cells to secrete insulin to match the level of whole-body insulin sensitivity. In addition, the β-cell function from the OGTT was calculated as the ratio of the area under the curve of C-peptide from 0 to 120 min to the area under the curve of glucose from 0 to 120 min as follows 28 : …”