Evaluation of Triglycerides-glucose (TyG) index in a cardiac rehabilitation program. Looking for associations and outcomes
Authors: Martinez Gonzalez R , Saldana Garcia J , Cobarro Galvez L , Torremocha Lopez A , Contreras Lorenzo C , Ugueto Rodrigo C , Castro Conde A 
Published: May 2023

Abstract

Funding Acknowledgements
Type of funding sources: None.
The Triglyceride-glucose (TyG) index is emerging as a novel marker of insulin resistance, metabolic syndrome and cardiovascular risk. The TyG index is calculated as Ln[(triglyceride [mg/dl]*fasting plasma glucose[mg/dl])/2]. It is being assessed in both primary and secondary prevention.
The aim of this study was to measure the TyG index in a group of patients in cardiac rehabilitation (CH) and relate it to cardiovascular events, the severity of coronary arterial disease (CAD) and compare it with other indexes for cardiovascular disease.
This unicenter, retrospective and observational study recruited patients who attended to CH program of a tertiary-level hospital between 1st January and 31st December, 2020. New cardiovascular events were registered until 15th October 2022. The TyG index was estimated according to the first blood sample at admission, we considered it abnormal above 8.8. The severity of CAD was measured using coronariography and stratified as single or multi-vessel (50% of stenosis in ≥2 main coronary arteries). MACCE was defined as myocardial infarction, stroke or cardiovascular death. We also calculated TG/HDL ratio (Triglycerides [mg/dl]/HDL cholesterol [mg/dl]), TC/HDL ratio (Total Cholesterol [mg/dl]/HDL [mg/dl]) and Remnant Cholesterol (non-HDL cholesterol [mg/dl] – LDL [mg/dl]). Statistical analyses were performed using R project.
A total of 238 patients were enrolled, 190 (79.8%) were men, mean age 60.5 ± 11.3 years. The main indication for CH was CAD. Percutaneous coronary intervention was done in 175 patients (73.5%), coronary artery bypass grafting was performed in 9 (3.8%); 36 (15.1%) individuals had suffered MACCE previously. During the follow up, 12 underwent another MACCE. The TyG index was statistically higher between patients who suffered MACCE (8.9±0.6, p&lt;0.01). This connection was also found with TG/HDL ratio (p=0.03), TC/HDL ratio (p&lt;0.01) and remnant (p=0.03)(Figure1). As for our cutoff of 8.8 the TyG index established a sensitivity of 49.7%, specificity of 72.5% and positive predictive value of 86.9% for MACCE. TyG index predicted better a second event (AUC=74.6%)(Figure2A) than TC/HDL (AUC=59.03%)(Figure2B). An elevated TyG index was linked with abnormal TG/HDL, TC/HDL remnants particles, VLDL, non-HDL, lower HDL and higher HbA1c and lower HDL but not with higher LDL and total cholesterol. There was no statistical relationship between TyG index with body mass index (p=0.14)(Figure2C) nor abdominal circumference (p=0.38)(Figure2D). Among patients with CAD, the average of stenotic vessels was 1.5±0.8. There were 7 in-stent-restenosis (ISR). We didn´t find a correlation between TyG index and multivessel disease (p=0.37), nor ISR (p=1.0).
TyG index is an easy and early sign of diabetic dyslipemia. In association with others indicators, it can help us to focus on those patients at high cardiovascular risk or with higher residual risk, specially nowadays that new non-statin therapies are about to come.