Triglyceride- Glucose Index Strongly Predicts Dysglycemia in First-Degree Relatives of People with Type 2 Diabetes Mellitus: A Retrospective Cohort Study.

BACKGROUND

First-degree relatives (FDRs) of people with type 2 diabetes mellitus (T2DM) are at substantially increased risk of dysglycemia. However, practical approaches for early risk stratification to dysglycemia remain limited. To determine the long-term incidence of dysglycemia and identify baseline metabolic predictors of progression to dysglycemia among normoglycemic FDRs of people with T2DM.

METHODS

A total of 169 normoglycemic first-degree relatives of patients with type 2 diabetes mellitus were included in this retrospective cohort study. All participants were recruited through the Clinical Research Unit of the Endocrine Research Center, Institute of Endocrinology and Metabolism, Tehran, Iran. Baseline evaluation included anthropometric measures, fasting and 2-hour post-load plasma glucose, HbA1c, lipid profile, insulin-related indices, renal parameters, and lifestyle factors. Dysglycemia was defined as progression to prediabetes or diabetes during follow-up. Independent predictors were identified using multivariable logistic regression, and predictive performance was assessed by receiver operating characteristic analysis.

RESULTS

The study included 169 participants with a mean age of 42.94±10.46 years at baseline. During a median follow-up of 7.1 years, 144 (85.2%) participants developed dysglycemia, including 129 (76.3%) who progressed to prediabetes and 15 (8.9%) who developed diabetes. In adjusted analyses, baseline triglyceride-glucose index and 2-hour post-load plasma glucose were independently associated with progression to dysglycemia. One standard deviation (0.25) increase in the triglyceride-glucose index was associated with 84% higher odds of dysglycemia (standardized odds ratio 1.84 (1.10-3.09); P = 0.020), while a comparable increase in 2-hour glucose was associated with 70 % higher odds (standardized odds ratio 1.70 (1.05-2.76); P = 0.031). The triglyceride-glucose index demonstrated modest discriminative ability, with an optimal cut-off value of 4.42.

CONCLUSION

Normoglycemic first-degree relatives of people with type 2 diabetes mellitus experience a high incidence of early glycemic deterioration. Triglyceride-glucose index and 2-hour post-load glucose are the main risk factors, supporting their integration into risk-based screening strategies in order to enable earlier, targeted prevention in high-risk populations.