Individual and joint effects of overweight/obesity and the triglyceride−glucose index on mortality risk in type 2 diabetic patients: a retrospective cohort study in China
Key result
Overweight status linked to ~27% lower all-cause mortality vs normal weight in T2D.
- aHR 0.73 for overweight vs normal weight (95% CI: 0.65-0.81)
- P<0.001
- n=15,796
Why the study?
The individual and combined effects of overweight/obesity and insulin resistance (reflected by the TyG index) on mortality among patients with T2DM remain incompletely elucidated.
Do overweight/obesity and a higher triglyceride-glucose (TyG) index reduce all-cause and cardiovascular mortality in adults with type 2 diabetes mellitus?
Population
15,796 T2DM adults aged >18 years from two hospitals in China
Comparison
Categories of BMI and TyG index quartiles
Design
Retrospective cohort study
Follow-up
Mean follow-up duration of 2.8 years
Authors
Discussion
Loading...
Member takes
Implication
Supports obesity paradox in T2DM; hypothesis-generating and should not yet change practice.
Key Points
- To assess the individual and combined associations of body mass index and the triglyceride-glucose index with all-cause and cardiovascular disease mortality in patients with type 2 diabetes.
- Conducted a retrospective cohort study of 15,796 adults (aged >18 years) with type 2 diabetes from two hospitals in China (2010–2023) with a mean follow-up of 2.8 years.
- Categorized body mass index into normal weight (18.5-24.9 kg/m²), overweight (25-29.9 kg/m²), and obesity (≥30 kg/m²), and calculated the triglyceride-glucose index from fasting triglycerides and fasting glucose.
- Employed multiple Cox proportional hazards models to estimate adjusted hazard ratios and 95% confidence intervals for mortality.
- Overweight and obesity were associated with lower all-cause mortality risk relative to normal weight (aHR: 0.73, 95% CI: 0.65−0.81 and aHR: 0.86, 95% CI: 0.74−1.00, respectively; 1,665 total deaths).
- Higher triglyceride-glucose index quartiles were associated with decreased all-cause mortality risk (Q3 aHR: 0.85, 95% CI: 0.74−0.98; Q4 aHR: 0.84, 95% CI: 0.72−0.97).
- The protective association of higher body mass index was more pronounced in patients aged 60 years or older.
Study Design
Type
Cohort (n=15,796)
Multicenter
Yes
Structured PICO
Do overweight/obesity and a higher triglyceride-glucose (TyG) index reduce all-cause and cardiovascular mortality in adults with type 2 diabetes mellitus?
P
Population
15,796 adults (aged >18 years) with type 2 diabetes mellitus (T2DM) from two hospitals in China
I
Intervention
Higher body mass index (overweight: 25-29.9 kg/m2, obesity: ≥30 kg/m2) and higher triglyceride-glucose (TyG) index
C
Comparator
Normal weight (BMI 18.5-24.9 kg/m2) and lower TyG index (Q1)
O
Outcome
All-cause mortalityhard clinical
Main Result
Effect estimate: aHR 0.73 for overweight vs normal weight (95% CI: 0.65-0.81) (95% CI 0.65-0.81)
Absolute Event Rate: 8.9% vs 12.3%
p-value: p=<0.001
In a large Chinese cohort of patients with T2DM, overweight/obesity and a higher TyG index were paradoxically associated with a lower risk of all-cause and cardiovascular mortality, supporting the existence of an obesity paradox in this population.
Limitations
- Observational design with potential residual confounding and reverse causation bias
- Use of BMI and TyG index as surrogate markers without longitudinal measurements
- Hospital-based cohort limiting generalizability to broader T2DM populations
- Exclusion of underweight individuals
- Potential collider bias due to conditioning on T2DM
- Lack of data on certain comorbidities and treatment changes over time
- Observational design cannot imply causality or validate prognostic use
- Potential for reverse causation (e.g., weight loss due to preexisting illness)
- Collider bias (e.g., medication use, healthcare access)
- Residual confounding
Cite This Study
Diwon et al. (2026) conducted a cohort in Adult patients (age >18) with type 2 diabetes mellitus from two hospitals in China (n=15,796). Overweight/obesity status and triglyceride-glucose (TyG) index level vs. Normal weight status and lower TyG index quartiles was evaluated on All-cause mortality (aHR 0.73 for overweight vs normal weight (95% CI: 0.65-0.81), 95% CI 0.65-0.81, p=<0.001). Overweight status reduced all-cause mortality risk by 27% compared to normal weight (aHR 0.73, 95% CI 0.65-0.81) among Chinese adults with type 2 diabetes over a mean 2.8-year follow-up.