

, Joon Ha2

1Institute of Medical Science, Yeungnam University College of Medicine, Daegu, Korea
2Department of Mathematics, Howard University, Washington, DC, USA
3Division of Endocrinology and Metabolism, Department of Internal Medicine, Yeungnam University College of Medicine, Daegu, Korea
Department of Mathematics, Howard University, Annex III, Room 222, College St. NW & 4th St. NW, Washington, DC, USA E-mail: joon.ha@howard.edu
Division of Endocrinology and Metabolism, Department of Internal Medicine, Yeungnam University Medical Center, Yeungnam University College of Medicine, 170 Hyeonchung-ro, Nam-gu, Daegu 42415, Korea E-mail: mjs7912@yu.ac.kr Copyright © 2026 Korean Diabetes Association
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
CONFLICTS OF INTEREST
Jun Sung Moon has been an editorial board member of the Diabetes & Metabolism Journal since 2016. He was not involved in the review process of this article. Otherwise, there was no conflict of interest.
FUNDING
This work was supported by dkNET Pilot Program of the National Institute of Diabetes & Digestive & Kidney Disease (Joon Ha), National Science Foundation (DMS 2401921) (Joon Ha), and the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. IRIS RS-2023-00219725) (Jun Sung Moon).
ACKNOWLEDGMENTS
During the preparation of this manuscript, the authors used ChatGPT5 for the purposes of language correction. The authors have reviewed and edited the output and take full responsibility for the content of this publication. All figures were created using BioRender.com.
| Index | Test method | Calculation formula | Phase-secretion | Study |
|---|---|---|---|---|
| HOMA-βa | Fasting measurement | Fasting glucose and insulin | NA | Matthews et al. (1985) [19] |
| Insulinogenic indexb | Standard OGTT | Glucose and insulin at time 0 and 30 min | Early phase-secretion | Tura et al. (2006) [80] |
| Oral DIc | Standard OGTT | Glucose and insulin at time 0, 30, 60, 90, 120 | Early phase-secretion | Matsuda et al. (1999) [85] |
| Model-derived BCF | Standard OGTT | Glucose and insulin at time 0, 30, 60, 90, 120 or 0, 60, 120 or 0, 30, 120 | Late phase-secretion | Ha et al. (2024) [16] |
| Model-derived DI | Standard OGTT | Glucose and insulin at time 0, 30, 60, 90, 120 or 0, 60, 120 or 0, 30, 120 | Late phase-secretion | Ha et al. (2025) [17] |
HOMA-β, homeostatic model assessment of β-cell function; NA, not available; OGTT, oral glucose tolerance test; DI, disposition index.
Notes on formulas:
a HOMA−B(%)=20×fasting insulin (μU/mL)/fasting glucose (mmol/L)−3.5 (units: fasting glucose: mmol/L, [If measured in mg/dL, convert: mmol/L=mg/dL/18]; fasting insulin: μU/mL)
b Insulinogenic index=(ΔI0−30/ΔG0−30): ΔInsulin=Insulin30 min−Insulin0 min; ΔGlucose=Glucose30 min−Glucose0 min
c Oral DI (Matsuda method): Insulinogenic index/Mastuda ISI
○
○ Fasting glucose and mean glucose are in mmol/L (or mg/dL converted to mmol/L).
○ Fasting insulin and mean insulin are in μU/mL.
○ Mean glucose and mean insulin are averages of all OGTT time points (usually 0, 30, 60, 90, 120 minutes).
| Study | Study | Intervention | No. of participants | BMI, kg/m2 | Remission cutoff | Remission outcome | β-Cell function indicators | Prognostic relevance |
|---|---|---|---|---|---|---|---|---|
| Lifestyle modification & Dietary intervention | ||||||||
| Retnakaran et al. (2025) [107] | Prospective Cohort (Canada) | Lifestyle (observational) | 468 (prediabetes) | 29.4 | Normoglycemia (OGTT) | 22.4% | ISSI-2 (↑), insulinogenic index/HOMA-IR (↑) | Recovery of β-cell function is the strongest independent determinant of remission. |
| Lean et al. (2018) [106] | DiRECT | Low-calorie diet | 298 | 35.1 | HbA1c <6.5% without medications | 46% at 12 mo | First-phase insulin response (↑), C-peptide (↑) | Early recovery of 1st phase-secretion predicts 2-yr sustained remission. |
| Taheri et al. (2020) [108] | DIADEM-I | Intensive lifestyle (Diet) | 147 | 34.5 | HbA1c <6.5% without medications | 61% at 12 mo | HOMA-β (↑), DI (↑) | Short T2DM duration (<3 yr) strongly associated with β-cell recovery. |
| Pharmacologic intervention | ||||||||
| Wu et al. (2025) [109] | IDEATE Trial (post hoc) | Short-term intensive insulin (SIIT) | 174 (T2DM) | 25.4 | HbA1c <6.5% after 1yr off-med | 50.6% at 1 yr | I30/G30 (↑); DI (↑); ISSI-2 (↑) | Restoration of β-cell function (especially DI) is the key driver for SIIT-induced remission. |
| Retnakaran et al. (2023) [110] | PREVAIL | 8 wk Glargine±Lispro/ Exenatide | 90 | 33.4 | HbA1c <6.5% off meds ≥3 m | 34.4% | ISSI-2, ISI/HOMA-IR, ΔC-pep0−120/ Δgluc0−120×Matsuda, ΔISR0−120/Δgluc0−120× Matsuda: ↑ | Baseline β-cell function is the pivotal determinant of SIIT-induced remission. |
| RISE Consortium (2019) [111] | RISE Adult | Liraglutide+Met vs. Insulin | 267 | 35.0 | β-Cell preservation (endpoint) | Transient (lost after withdrawal) | Hyperglycemic clamp (SSCP, ACPRmax, ACPRg, M/I) ↑; returned to baseline after 3-mo washout | Pharmacotherapy may delay decline but lacks durable ‘remission’ effect vs. surgery. |
| Weng et al. (2008) [112] | Short-term intensive therapy | Intensive Insulin (CSII or MDI, 2 wk) vs. OHA | 382 | 25.0 | Normoglycemia for 2 wk then off meds | 1-yr Remission: CSII 51.1%, MDI 44.9% vs. OHA 26.7% | HOMA-β (↑), AIR (↑) | Early ‘β-cell rest’ restores 1st phase-secretion, enabling long-term drug-free state. |
| Bariatric and metabolic surgery | ||||||||
| Luo et al. (2021) [113] | Prospective Chinese T2DM (RYGB vs. SG; BMI 27.5–32.5) | LRYGB vs. LSG; prospective | 36 | 27.5–32.5 (overweight/ obese, non-morbid) | Triple composite endpoint (glycemic targets off meds) | Composite remission 52.6% (RYGB) vs. 29.4% (LSG) at 6 mo | DI increased (RYGB 1.14→7.11; SG 1.25→5.60); IGI30 decreased; clamp GDR increased | DI improvement and insulin sensitivity recovery aligned with short-term remission. |
| Fatima et al. (2022) [114] | Oseberg RCT (RYGB vs. SG) | RYGB vs. SG (randomized, triple-blind) | 106 | Obesity eligible for bariatric surgery; NR | HbA1c ≤6.0% without meds at 1 yr | RYGB 77% vs. SG 48% at 1 yr | Fasting ISR (↑)/ iAUC0−180 ISR (↑)/ β-glucose sensitivity (↑) | Diabetes remission at 1 yr was associated with higher β-GS |
| Purnell et al. (2018) [115] | LABS-3 diabetes cohort (2-yr follow-up) | RYGB mechanistic study (T2DM vs. NGT) | 62 (T2DM 40) | 47.9 | HbA1c <6.5% (or FPG ≤125 mg/dL) without meds | 91% | DI (FSIVGTT) (↑) 3–9 fold; AIRglu (↑) | β-Cell recovery and DI improvement underpin long-term glycemic gains after RYGB |
BMI, body mass index; OGTT, oral glucose tolerance test; ISSI-2, insulin secretion–sensitivity index-2; HOMA-IR, homeostasis model assessment of insulin resistance; DiRECT, Diabetes Remission Clinical Trial; HbA1c, glycosylated hemoglobin; DIADEM-I, Diabetes Intervention Accentuating Diet and Enhancing Metabolism; HOMA-β, homeostasis model assessment of β-cell function; DI, disposition index; T2DM, type 2 diabetes mellitus; IDEATE, Intermittent intensive Diet and Enhanced physical Activity on glycemic control in newly diagnosed Type 2 diabEtes study; I30/G30, 30-minute insulin/30-minute glucose; PREVAIL, Preserving Beta-cell Function in Type 2 Diabetes With Exenatide and Insulin; ISI, insulin sensitivity index; ISR, insulin secretion rate; RISE, Restoring Insulin Secretion; SSCP, steady-state C-peptide; ACPRmax, maximum acute Cpeptide response; ACPRg, glucose-potentiated acute C-peptide response; M/I, clamp-derived insulin sensitivity; CSII, continuous subcutaneous insulin infusion; MDI, multiple daily injection; OHA, oral hypoglycemic agent; AIR, acute insulin response; RYGB, Roux-en-Y gastric bypass; SG, sleeve gastrectomy; LRYGB, laparoscopic Roux-en-Y gastric bypass; LSG, laparoscopic sleeve gastrectomy; IGI30, insulinogenic index at 30 minutes; GDR, glucose disposal rate; RCT, randomized controlled trial; NR, not reported; iAUC, incremental area under the curve; β-GS, β-cell glucose sensitivity; LABS-3, Longitudinal Assessment of Bariatric Surgery; NGT, normal glucose tolerance; FPG, fasting plasma glucose; FSIVGTT, frequently sampled intravenous glucose tolerance test; AIRglu, acute insulin response to glucose.
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| Index | Test method | Calculation formula | Phase-secretion | Study |
|---|---|---|---|---|
| HOMA-β |
Fasting measurement | Fasting glucose and insulin | NA | Matthews et al. (1985) [19] |
| Insulinogenic index |
Standard OGTT | Glucose and insulin at time 0 and 30 min | Early phase-secretion | Tura et al. (2006) [80] |
| Oral DI |
Standard OGTT | Glucose and insulin at time 0, 30, 60, 90, 120 | Early phase-secretion | Matsuda et al. (1999) [85] |
| Model-derived BCF | Standard OGTT | Glucose and insulin at time 0, 30, 60, 90, 120 or 0, 60, 120 or 0, 30, 120 | Late phase-secretion | Ha et al. (2024) [16] |
| Model-derived DI | Standard OGTT | Glucose and insulin at time 0, 30, 60, 90, 120 or 0, 60, 120 or 0, 30, 120 | Late phase-secretion | Ha et al. (2025) [17] |
| Study | Study | Intervention | No. of participants | BMI, kg/m2 | Remission cutoff | Remission outcome | β-Cell function indicators | Prognostic relevance |
|---|---|---|---|---|---|---|---|---|
| Lifestyle modification & Dietary intervention | ||||||||
| Retnakaran et al. (2025) [107] | Prospective Cohort (Canada) | Lifestyle (observational) | 468 (prediabetes) | 29.4 | Normoglycemia (OGTT) | 22.4% | ISSI-2 (↑), insulinogenic index/HOMA-IR (↑) | Recovery of β-cell function is the strongest independent determinant of remission. |
| Lean et al. (2018) [106] | DiRECT | Low-calorie diet | 298 | 35.1 | HbA1c <6.5% without medications | 46% at 12 mo | First-phase insulin response (↑), C-peptide (↑) | Early recovery of 1st phase-secretion predicts 2-yr sustained remission. |
| Taheri et al. (2020) [108] | DIADEM-I | Intensive lifestyle (Diet) | 147 | 34.5 | HbA1c <6.5% without medications | 61% at 12 mo | HOMA-β (↑), DI (↑) | Short T2DM duration (<3 yr) strongly associated with β-cell recovery. |
| Pharmacologic intervention | ||||||||
| Wu et al. (2025) [109] | IDEATE Trial (post hoc) | Short-term intensive insulin (SIIT) | 174 (T2DM) | 25.4 | HbA1c <6.5% after 1yr off-med | 50.6% at 1 yr | I30/G30 (↑); DI (↑); ISSI-2 (↑) | Restoration of β-cell function (especially DI) is the key driver for SIIT-induced remission. |
| Retnakaran et al. (2023) [110] | PREVAIL | 8 wk Glargine±Lispro/ Exenatide | 90 | 33.4 | HbA1c <6.5% off meds ≥3 m | 34.4% | ISSI-2, ISI/HOMA-IR, ΔC-pep0−120/ Δgluc0−120×Matsuda, ΔISR0−120/Δgluc0−120× Matsuda: ↑ | Baseline β-cell function is the pivotal determinant of SIIT-induced remission. |
| RISE Consortium (2019) [111] | RISE Adult | Liraglutide+Met vs. Insulin | 267 | 35.0 | β-Cell preservation (endpoint) | Transient (lost after withdrawal) | Hyperglycemic clamp (SSCP, ACPRmax, ACPRg, M/I) ↑; returned to baseline after 3-mo washout | Pharmacotherapy may delay decline but lacks durable ‘remission’ effect vs. surgery. |
| Weng et al. (2008) [112] | Short-term intensive therapy | Intensive Insulin (CSII or MDI, 2 wk) vs. OHA | 382 | 25.0 | Normoglycemia for 2 wk then off meds | 1-yr Remission: CSII 51.1%, MDI 44.9% vs. OHA 26.7% | HOMA-β (↑), AIR (↑) | Early ‘β-cell rest’ restores 1st phase-secretion, enabling long-term drug-free state. |
| Bariatric and metabolic surgery | ||||||||
| Luo et al. (2021) [113] | Prospective Chinese T2DM (RYGB vs. SG; BMI 27.5–32.5) | LRYGB vs. LSG; prospective | 36 | 27.5–32.5 (overweight/ obese, non-morbid) | Triple composite endpoint (glycemic targets off meds) | Composite remission 52.6% (RYGB) vs. 29.4% (LSG) at 6 mo | DI increased (RYGB 1.14→7.11; SG 1.25→5.60); IGI30 decreased; clamp GDR increased | DI improvement and insulin sensitivity recovery aligned with short-term remission. |
| Fatima et al. (2022) [114] | Oseberg RCT (RYGB vs. SG) | RYGB vs. SG (randomized, triple-blind) | 106 | Obesity eligible for bariatric surgery; NR | HbA1c ≤6.0% without meds at 1 yr | RYGB 77% vs. SG 48% at 1 yr | Fasting ISR (↑)/ iAUC0−180 ISR (↑)/ β-glucose sensitivity (↑) | Diabetes remission at 1 yr was associated with higher β-GS |
| Purnell et al. (2018) [115] | LABS-3 diabetes cohort (2-yr follow-up) | RYGB mechanistic study (T2DM vs. NGT) | 62 (T2DM 40) | 47.9 | HbA1c <6.5% (or FPG ≤125 mg/dL) without meds | 91% | DI (FSIVGTT) (↑) 3–9 fold; AIRglu (↑) | β-Cell recovery and DI improvement underpin long-term glycemic gains after RYGB |
HOMA-β, homeostatic model assessment of β-cell function; NA, not available; OGTT, oral glucose tolerance test; DI, disposition index. Notes on formulas: HOMA−B(%)=20×fasting insulin (μU/mL)/fasting glucose (mmol/L)−3.5 (units: fasting glucose: mmol/L, [If measured in mg/dL, convert: mmol/L=mg/dL/18]; fasting insulin: μU/mL) Insulinogenic index=(ΔI0−30/ΔG0−30): ΔInsulin=Insulin30 min−Insulin0 min; ΔGlucose=Glucose30 min−Glucose0 min Oral DI (Matsuda method): Insulinogenic index/Mastuda ISI ○ ○ Fasting glucose and mean glucose are in mmol/L (or mg/dL converted to mmol/L). ○ Fasting insulin and mean insulin are in μU/mL. ○ Mean glucose and mean insulin are averages of all OGTT time points (usually 0, 30, 60, 90, 120 minutes).
BMI, body mass index; OGTT, oral glucose tolerance test; ISSI-2, insulin secretion–sensitivity index-2; HOMA-IR, homeostasis model assessment of insulin resistance; DiRECT, Diabetes Remission Clinical Trial; HbA1c, glycosylated hemoglobin; DIADEM-I, Diabetes Intervention Accentuating Diet and Enhancing Metabolism; HOMA-β, homeostasis model assessment of β-cell function; DI, disposition index; T2DM, type 2 diabetes mellitus; IDEATE, Intermittent intensive Diet and Enhanced physical Activity on glycemic control in newly diagnosed Type 2 diabEtes study; I30/G30, 30-minute insulin/30-minute glucose; PREVAIL, Preserving Beta-cell Function in Type 2 Diabetes With Exenatide and Insulin; ISI, insulin sensitivity index; ISR, insulin secretion rate; RISE, Restoring Insulin Secretion; SSCP, steady-state C-peptide; ACPRmax, maximum acute Cpeptide response; ACPRg, glucose-potentiated acute C-peptide response; M/I, clamp-derived insulin sensitivity; CSII, continuous subcutaneous insulin infusion; MDI, multiple daily injection; OHA, oral hypoglycemic agent; AIR, acute insulin response; RYGB, Roux-en-Y gastric bypass; SG, sleeve gastrectomy; LRYGB, laparoscopic Roux-en-Y gastric bypass; LSG, laparoscopic sleeve gastrectomy; IGI30, insulinogenic index at 30 minutes; GDR, glucose disposal rate; RCT, randomized controlled trial; NR, not reported; iAUC, incremental area under the curve; β-GS, β-cell glucose sensitivity; LABS-3, Longitudinal Assessment of Bariatric Surgery; NGT, normal glucose tolerance; FPG, fasting plasma glucose; FSIVGTT, frequently sampled intravenous glucose tolerance test; AIRglu, acute insulin response to glucose.
