Adipo-B Index as a Novel Predictor of Beta-Cell Secretory Function Without Measuring Insulin: Cross-Therapeutic Validation Against C-Peptide Index in Treatment-Naive Type 2 Diabetes

@misc{kutoh2026adipob,
  title = {{Adipo-B Index as a Novel Predictor of Beta-Cell Secretory Function Without Measuring Insulin: Cross-Therapeutic Validation Against C-Peptide Index in Treatment-Naive Type 2 Diabetes}},
  author = {E. Kutoh and A. Kuto},
  howpublished = {medRxiv},
  year = {2026},
  month = oct,
  doi = {10.64898/2026.10.24.26366378},
  url = {https://www.medrxiv.org/content/10.64898/2026.10.24.26366378v1},
  note = {CC BY-ND},
}

TY  - UNPB
TI  - Adipo-B Index as a Novel Predictor of Beta-Cell Secretory Function Without Measuring Insulin: Cross-Therapeutic Validation Against C-Peptide Index in Treatment-Naive Type 2 Diabetes
AU  - E. Kutoh
AU  - A. Kuto
PY  - 2026
DA  - 2026/10/24
PB  - medRxiv
DO  - 10.64898/2026.10.24.26366378
UR  - https://www.medrxiv.org/content/10.64898/2026.10.24.26366378v1
AB  - OBJECTIVEThe adipo-B index (adipo-IR divided by HOMA-B) was introduced as an integrator of adipose tissue insulin resistance and pancreatic beta-cell function. Algebraic simplification reveals that insulin cancels from the formula, yielding FFA x (FBG-63)/360 -- a composite of circulating free fatty acids and ambient glycemia. We investigated whether this index predicts beta-cell secretory capacity measured by HOMA-B and C-peptide index (CPR-index) across four therapeutic strategies.  RESEARCH DESIGN AND METHODSA total of 253 treatment-naive subjects with T2DM received monotherapy with modified Japanese diet for diabetes (MJDD, n=61), canagliflozin (n=67), pioglitazone (n=62), or sitagliptin (n=63). Correlations between baseline adipo-B and baseline beta-cell indices, and between their longitudinal changes, were examined. This is a prospective, non-randomized observational study.  RESULTSAt baseline, adipo-B showed significant negative correlations with HOMA-B with all the subjects. At 3 months, adipo-B significantly decreased and HOMA-B significantly increased with all the therapeutic groups. CPR-index significantly improved with canagliflozin and sitagliptin. Pioglitazone showed a trend toward improvement while MJDD demonstrated no changes. Changes in adipo-B ({Delta}adipo-B) significantly and negatively correlated with changes in both HOMA-B and CPR-index in MJDD, canagliflozin, and sitagliptin. With pioglitazone, no such correlations were observed -- consistent with the previously reported bidirectional regulation of insulin secretion by pioglitazone depending on baseline insulin secretory status.  CONCLUSIONSThe adipo-B index predicted beta-cell secretory capacity -- assessed independently by conventional beta-cell indices -- without requiring insulin or C-peptide measurement. These findings suggest adipo-B may serve as a cost-effective surrogate for assessment of beta-cell function in routine clinical settings.  ARTICLE HIGHLIGHTSO_LIWhy did we undertake this study? Insulin cancels algebraically from the adipo-B formula, questioning its validity. We tested if adipo-B predicts beta-cell function using the insulin-independent C-peptide index. C_LIO_LIWhat is the specific question we wanted to answer? Does adipo-B predict beta-cell secretory capacity (via HOMA-B and C-peptide index) without requiring insulin or C-peptide measurements? C_LIO_LIWhat did we find? Cross-sectionally, baseline adipo-B negatively correlated with HOMA-B and CPR-index. Longitudinally, {Delta}adipo-B negatively correlated with {Delta}HOMA-B and {Delta}CPR-index for MJDD, canagliflozin, and sitagliptin--but not pioglitazone, reflecting its bidirectional beta-cell regulation. C_LIO_LIWhat are the implications? Adipo-B predicts beta-cell capacity without insulin or C-peptide testing, offering a cost-effective surrogate for routine and resource-limited clinical settings. C_LI
ER  -