Characteristics of OGTT and Correlation Between the Insulin to C-Peptide Molar Ratio, HOMA-IR, and Insulin Antibodies in T2DM Patients

Abstract

Purpose

The purpose of our study was to analyze the characteristics of OGTT and the correlation between the insulin to C-peptide molar ratio (ICPR), HOMA-IR and insulin antibodies (IAs) in T2DM patients.

Patients and Methods

A total of 77 T2DM patients were included and divided into the IA+ group (25 patients) and IA- group (52 patients). The values of serum glucose, insulin, and C-peptide testing during 2-h OGTT were summarized comparatively, and ROC was made to analyze the predictive value of ICPR for IAs.

Results

At each time point of OGTT, there was no significant difference in serum glucose and C-peptide changes (p>0.05). Serum insulin levels in positive patients were elevated or not at different time points of the OGTT but ICPR was significantly different (P<0.05) in the two groups. Spearman correlation coefficient analysis showed that the presence of insulin antibodies was correlated with ICPR, but not with HOMA-IR, and ICPR-2h had a better prediction capacity (AUC=0.735, the optimal cutoff-point=0.11, Se=0.760, Sp=0.635).

Conclusion

T2DM patients with IAs showed no difference in serum glucose and serum C-peptide changes, but elevated or not insulin levels on the OGTTs, compared with negative patients. ICPR-2h can be a preliminary diagnostic index to timely predict IAs in T2DM patients.

Keywords:

• insulin therapy
• insulin resistance
• oral glucose tolerance test
• receiver operating characteristic curve

Consent for Publication

All authors listed meet the authorship criteria according to the latest guidelines of the International Committee of Medical Journal Editors. All authors agree with the manuscript and certify that they have participated sufficiently in the work to take public responsibility for the appropriateness of the experimental design and method, and the collection, analysis, and interpretation of the data.

Acknowledgments

The authors would like to sincerely thank all the patients who participated in this study.

The work was supported by Special Fund for Introducing High-level Health Talents in Xiamen (code number PM202204140001) and XMU Training Program of Innovation and Entrepreneurship for Undergraduates (grant number S202210384849).

Author Contributions

All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Disclosure

The authors report no conflicts of interest in this work.