Association Between Triglyceride-Glucose Index and HbA1c in Prediabetes: A Preliminary Evaluation of a Potential Biomarker

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Journal of MedVerse Research & Practice

ISSN: 3107-4278

Association Between Triglyceride-Glucose Index and HbA1c in

Prediabetes: A Preliminary Evaluation of a Potential Biomarker

Dr. Dharani A

, Dr. Aravind Raj R

Postgraduate, Associate Professor

Department of Community Medicine, Coimbatore Medical College & Hospital

Email: sangitas963@gmail.com

Submission Date: 24.09.2025

Accepted Date: 22.10.2025

Published Date: 31.10.2025

DOI: 10.65188/nurexus.1047

article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits

unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.

Abstract

Background: Prediabetes is an intermediate metabolic state associated with a high risk of progression to type 2

diabetes mellitus. Identifying early markers of insulin resistance is essential to prevent disease progression. The

Triglyceride Glucose (TyG) index has emerged as a simple and cost-effective surrogate marker of insulin resistance,

but its utility in prediabetic individuals remains underexplored.

Aim: To evaluate the Triglyceride Glucose index and its association with HbA1c among prediabetic patients and

assess its role as a potential early biomarker of insulin resistance.

Methodology: A preliminary cross-sectional study was conducted among prediabetic subjects and healthy controls.

Fasting plasma glucose, triglycerides, and HbA1c levels were measured and the TyG index was calculated.

Correlation analysis between HbA1c and TyG index was performed.

Results: Prediabetic individuals showed higher fasting glucose, triglycerides, HbA1c, and TyG index values

compared to controls. A significant positive correlation was observed between TyG index and HbA1c among

prediabetic participants (r = 0.32, p = 0.022), indicating that higher TyG values are associated with poorer glycemic

control.

Conclusion: The TyG index demonstrated comparable utility to HbA1c in identifying prediabetes and offers a

simple, accessible, and cost-effective marker for early detection of insulin resistance. Routine use of the TyG index

may support early intervention strategies in high-risk individuals. Larger longitudinal studies are recommended to

validate these findings and establish population-specific cutoff values.

Keywords: Prediabetes, Triglyceride Glucose Index, TyG Index, HbA1c, Insulin Resistance, Biomarker, Metabolic

Risk, Early Detection, Type 2 Diabetes Prevention

Introduction

Diabetes mellitus (DM) is one of the most common endocrine disorders globally, and its prevalence

continues to rise in both developed and developing countries. According to the International Diabetes

Federation (IDF), approximately 537 million adults were living with diabetes in 2021, and this number is

projected to increase to 783 million by 2045 if effective preventive strategies are not implemented [1].

India, often considered the diabetes capital of the world, currently has more than 77 million individuals

diagnosed with diabetes and an estimated 25 million with prediabetes [2].

Prediabetes is defined by impaired fasting glucose (IFG), impaired glucose tolerance (IGT), or glycated

haemoglobin (HbA1c) levels ranging from 5.7 percent to 6.4 percent [3]. It represents an intermediate

metabolic state between normal glucose regulation and type 2 diabetes mellitus (T2DM). Individuals with

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prediabetes are at a significantly higher risk of progressing to T2DM, and they also experience early

metabolic abnormalities, including cardiovascular disease, microvascular complications, and metabolic

syndrome, even before diabetes develops [4][5].

Insulin resistance (IR) represents a central mechanism linking prediabetes to overt diabetes and associated

complications. It impairs glucose uptake and utilization, leading to hyperglycaemia and compensatory

hyperinsulinemia. Additionally, IR contributes to dyslipidaemia, systemic inflammation, oxidative stress,

and endothelial dysfunction [6]. Therefore, early identification of IR in prediabetic individuals is essential

for timely intervention and prevention of diabetes progression.

The triglyceride-glucose (TyG) index, introduced by Simental-Mendía et al. in 2008, is a reliable surrogate

marker of insulin resistance, calculated using fasting triglycerides (TG) and fasting plasma glucose (FPG)

levels [7]. It is derived based on the established association between dyslipidaemia and insulin resistance.

The TyG index is computed using the formula: TyG = ln (fasting triglycerides × fasting plasma glucose) /

2. The index offers advantages of simplicity, affordability, and accessibility, since it utilizes routine

biochemical parameters. This makes it feasible for use in large-scale screening and primary healthcare

settings, unlike the hyperinsulinemia-euglycemic clamp method or HOMA-IR, which require specialized

testing and fasting insulin levels [8][9].

Numerous studies have demonstrated strong correlations between the TyG index and the hyperinsulinemia-

euglycemic clamp test, as well as with HOMA-IR [8,9]. Furthermore, elevated TyG values have been

linked to increased risk of T2DM, metabolic syndrome, non-alcoholic fatty liver disease, and

cardiovascular diseases [10-15]. On the other hand, HbA1c is a well-established biomarker for long-term

glycaemic control and is used widely for the diagnosis and monitoring of diabetes and prediabetes.

Studying the association between TyG index and HbA1c in prediabetic individuals may therefore help

determine whether TyG can serve as a dual indicator reflecting both lipid-related insulin resistance and

long-term glycaemic burden.

Although global evidence supports the utility of the TyG index as a marker of metabolic risk, limited data

exist from India, particularly among prediabetic populations. There is a lack of studies from South India,

especially in Karnataka, assessing the association between TyG index and HbA1c. Early identification of

high-risk individuals using cost-effective surrogate markers such as TyG may support timely preventive

strategies and reduce diabetes burden in the region [16-19].

The present study aims to assess TyG index levels and examine their association with HbA1c in prediabetic

patients compared to healthy controls. The objectives are: (1) To estimate fasting plasma glucose,

triglyceride, and HbA1c levels in prediabetic individuals and healthy controls. (2) To calculate the TyG

index using the formula TyG = ln (fasting triglycerides × fasting plasma glucose) / 2. (3) To determine the

correlation between TyG index and HbA1c levels in the study population.

Materials & Methods

This hospital-based cross-sectional case–control study was conducted in the Department of General

Medicine at Raja Rajeswari Medical College and Hospital (RRMCH), Bengaluru, after obtaining

Institutional Ethics Committee approval and informed consent from all participants. The study included 100

subjects, comprising 50 prediabetic patients attending the Medicine OPD and 50 age- and sex-matched

apparently healthy controls. Prediabetes was diagnosed according to American Diabetes Association

(ADA) criteria, and individuals aged 30 to 60 years were eligible for inclusion. Subjects with known type 2

diabetes mellitus, chronic systemic illnesses such as liver cirrhosis, HIV infection, chronic kidney disease,

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pancreatic disorders, pregnant or lactating women, and those taking medications influencing glucose or

lipid metabolism including corticosteroids, nicotinic acid, fibrates, statins, or other anti-dyslipidemia

agents, were excluded. After overnight fasting for 8 to 10 hours, venous blood samples were collected

under aseptic precautions to measure fasting plasma glucose by the glucose oxidase–peroxidase method,

serum triglycerides using the enzymatic colorimetric method, and HbA1c using high-performance liquid

chromatography (HPLC). The triglyceride–glucose (TyG) index was calculated using the formula: TyG =

ln (fasting triglycerides × fasting plasma glucose) / 2. Data were entered in Microsoft Excel and analyzed

using IBM SPSS version 25.0. Results were expressed as mean ± standard deviation, and group

comparisons were performed using the independent sample t-test. Pearson correlation analysis was

employed to assess the association between the TyG index and HbA1c levels, and a p-value < 0.05 was

considered statistically significant.

Institutional Ethics Committee approval was obtained from Coimbatore Medical College & Hospital (Ref

No: CMCH/IEC/2024/96841). A detailed Participant Information Sheet was provided to all participants,

and written informed consent was obtained prior to their inclusion in the study.

Results

Table 1: Baseline Characteristics of Study Participants

Variable

Cases (n = 50)

Controls (n = 50)

p-value

Age (years, Mean ± SD)

45.2 ± 6.5

44.8 ± 6.1

0.72

Sex (Male/Female)

28 / 22

27 / 23

0.84

BMI (kg/m², Mean ± SD)

26.5 ± 3.2

24.8 ± 2.9

0.041*

The baseline characteristics of the study participants are summarized in the table. The mean age of the

cases (45.2 ± 6.5 years) was comparable to that of the controls (44.8 ± 6.1 years), with no significant

difference (p = 0.72). The sex distribution was also similar between the two groups (28 males/22 females

vs. 27 males/23 females, p = 0.84). However, the mean BMI was significantly higher among cases (26.5 ±

3.2 kg/m²) compared to controls (24.8 ± 2.9 kg/m²), indicating a statistically significant association with

prediabetes (p = 0.041).

Table 2: Comparison of Glycemic Parameters

Parameter

Cases (n = 50)

Controls (n = 50)

p-value

Fasting Blood Glucose (mg/dl)

104 ± 8.6

89 ± 7.5

0.022*

HbA1c (%)

5.9 ± 0.3

5.2 ± 0.2

0.022*

The comparison of biochemical parameters between the two groups shows that prediabetic cases had

significantly higher fasting blood glucose levels (104 ± 8.6 mg/dl) compared to controls (89 ± 7.5 mg/dl, p

= 0.022). Similarly, HbA1c levels were elevated in cases (5.9 ± 0.3%) relative to controls (5.2 ± 0.2%, p =

0.022). These findings highlight a clear glycemic derangement among prediabetic individuals when

compared with healthy controls.

Table 3: Comparison of Lipid Profile

Parameter

Cases (n = 50)

Controls (n = 50)

p-value

Triglycerides (mg/dl)

203 ± 22.4

114 ± 18.7

0.022*

Total Cholesterol (mg/dl)

184 ± 25

176 ± 21

0.11

HDL-C (mg/dl)

42 ± 5

46 ± 6

0.09

The lipid profile comparison between cases and controls indicates that prediabetic individuals had

significantly higher triglyceride levels (203 ± 22.4 mg/dl) compared to controls (114 ± 18.7 mg/dl, p =

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0.022), suggesting early dyslipidemic changes associated with prediabetes. Although total cholesterol and

HDL-C levels were slightly different between groups (184 ± 25 mg/dl vs. 176 ± 21 mg/dl and 42 ± 5 mg/dl

vs. 46 ± 6 mg/dl, respectively), these differences were not statistically significant (p > 0.05), indicating that

triglycerides may be a more sensitive marker of metabolic disturbance in the prediabetic state.

Table 4: TyG Index between Groups

Group

Mean TyG Index ± SD

Cases

4.96 ± 0.2

0.349

Controls

4.58 ± 0.15

The mean TyG index was higher in prediabetic cases (4.96 ± 0.2) compared to controls (4.58 ± 0.15);

however, this difference did not reach statistical significance (p = 0.349). This suggests a trend toward

increased insulin resistance among prediabetic individuals, although larger studies may be needed to

confirm the significance of this association.

Table 5: Comparison of Biochemical Parameters between Cases and Controls

Group

HbA1c (%)

FBS (mg/dl)

TG (mg/dl)

TyG Index

p-value

Cases

5.9

104

203

4.96

0.022*

Controls

5.2

114

4.58

0.349

The comparison of key biochemical parameters between cases and controls shows that prediabetic

individuals had significantly higher HbA1c (5.9% vs. 5.2%), fasting blood glucose (104 vs. 89 mg/dl), and

triglyceride levels (203 vs. 114 mg/dl) compared to healthy controls, with statistical significance observed

for HbA1c, FBS, and TG (p = 0.022). The TyG index was higher in cases (4.96) than in controls (4.58),

indicating a trend toward increased insulin resistance, though this difference was not statistically significant

(p = 0.349). These findings collectively suggest early glycemic and lipid abnormalities in prediabetic

subjects.

Figure 1: Comparison of HBA1C between Cases and Controls

Discussion

Prediabetes represents an intermediate state of hyperglycaemia in which plasma glucose levels are above

normal but below the diagnostic threshold for diabetes. Individuals with prediabetes carry a substantially

increased risk of developing type 2 diabetes mellitus (T2DM) and cardiovascular complications if early

intervention is not initiated. Insulin resistance (IR) plays a central role in the transition from prediabetes to

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diabetes by impairing cellular glucose uptake, resulting in hyperglycaemia and compensatory

hyperinsulinemia. Elevated triglyceride levels further exacerbate glycaemic dysregulation by interfering

with insulin signalling pathways, reinforcing IR as a key modifiable contributor to diabetes progression, as

described by Tabák et al. [1] and Huang et al. [2].

The Triglyceride-Glucose (TyG) index has gained recognition as a simple, cost-effective, and reliable

surrogate marker of insulin resistance, as it incorporates fasting triglyceride and fasting glucose levels. This

index reflects early metabolic abnormalities that may not be captured by fasting glucose or HbA1c alone.

Simental-Mendía et al. [3] first proposed the TyG index as a surrogate marker of insulin resistance. In the

present study, prediabetic subjects demonstrated significantly higher fasting glucose, HbA1c, and

triglyceride levels compared to healthy controls, consistent with the coexistence of dysglycaemia and

dyslipidaemia in the prediabetic stage. Similar metabolic alterations were reported by Vasques et al. [4],

who observed higher TyG values among insulin-resistant individuals using hyperglycaemic clamp

validation.

A noteworthy finding of the present study was the positive correlation between TyG index and HbA1c

among prediabetic participants, indicating that higher TyG values are associated with poorer glycaemic

control. This observation aligns with findings by Venkateshan et al. [5], who demonstrated a significant

correlation between TyG index and HbA1c in prediabetic individuals. Comparable associations were also

reported by Lee et al. [6], who identified strong links between the TyG index, insulin resistance, and

metabolic syndrome in a Korean population. Furthermore, Zhang et al. [7] reported that elevated TyG

values predicted future development of T2DM and cardiovascular disease, reinforcing its utility as an early

biomarker of metabolic risk.

Although the mean TyG index was higher in prediabetic subjects than in healthy controls, the difference

did not reach statistical significance. This lack of significance may be attributable to the relatively small

sample size and cross-sectional study design, which may limit the detection of modest differences.

Nevertheless, the observed upward trend is consistent with reports by Simental-Mendía et al. [3] and

Vasques et al. [4], both of whom documented significantly higher TyG values in insulin-resistant and

prediabetic populations.

From a clinical perspective, the TyG index offers several advantages, including low cost, ease of

calculation, and reliance on routinely available laboratory parameters. The observed correlation between

TyG index and HbA1c in the present study suggests that combined use of these markers may enhance early

identification of individuals at high metabolic risk. Several recent studies have emphasized the expanding

clinical relevance of the TyG index in predicting prediabetes, diabetes, and cardiovascular outcomes, as

highlighted by Ye et al. [19], Liu et al. [20], Shi et al. [21], Park et al. [22], Wen et al. [23], and Liu et al.

[24]. Early screening using the TyG index may therefore play a crucial role in delaying or preventing the

progression from prediabetes to overt diabetes.

Conclusion

The present study demonstrates that the Triglyceride-Glucose (TyG) index shows significant potential as a

reliable biomarker for identifying individuals with prediabetes and assessing insulin resistance, exhibiting

utility comparable to HbA1c. Since the TyG index is derived from routine laboratory tests, including

fasting plasma glucose and fasting triglycerides, it is simple, inexpensive, and easily accessible across

healthcare settings. This makes it a particularly valuable tool in resource-constrained environments where

advanced glycemic markers may not be routinely available. Based on our findings, the TyG index can serve

as an effective adjunct, and in certain circumstances a viable alternative, to HbA1c for early detection and

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risk stratification in prediabetes and metabolic dysregulation. Therefore, integration of the TyG index into

clinical evaluation protocols may support timely intervention and prevention of progression to type 2

diabetes.

Conflict of Interest: Nil

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in Chinese elderly individuals. Sci Rep. 2024;14(1):16033. doi:10.1038/s41598-024-67081-y.

21. Shi Y, Yu C. U shape association between triglyceride glucose index and congestive heart failure in patients

with diabetes and prediabetes. Nutr Metab (Lond). 2024;21:42. doi:10.1186/s12986-024-00819-7.

22. Park MS, Lee SH, Kim YS. Triglyceride-glucose index predicts future metabolic syndrome in an adult

population: A cohort study. Ann Clin Nutr Metab. 2024;16(3):168–75. doi:10.15747/ACNM.2024.16.3.168.

23. Wen Z, Zhang Y, Li Y, et al. The role of Triglyceride-Glucose index in predicting pre-DM and type 2

diabetes mellitus: a systematic review and meta-analysis. Sci Rep. 2025;15(1):12293. doi:10.1038/s41598-

025-12293-z.

24. Liu C, Zhang Y, Li Y, et al. The association between the triglyceride–glucose index and cardiovascular

disease risk in the U.S. population aged ≤65 years with prediabetes and diabetes. Cardiovasc Diabetol.

2024;23(1):61. doi:10.1186/s12933-024-02261-8.