Association between insulin resistant surrogate index and arterial stiffness in hypertensive population: a five year follow-up cohort study

Abstract Background Causal association between triglyceride-glucose (TyG) index and triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio with arterial stiffness remains unclear. This study aims to assess the effect of TyG index and TG/HDL-C ratio on the incidence of arterial stiffness in hypertensive population, and identify the susceptible subgroups. Methods This study enrolled 1201 hypertensive participants without arterial stiffness aged 18 or above in 2013 and 2014 as baseline. Physical examination and biochemical test including fasting blood glucose (FBG), TG, HDL-C were measured. The TyG index was denoted as ln[TG*FBG/2]. Incident arterial stiffness cases were confirmed during the following annual examination by brachial-ankle pulse wave velocity (baPWV, > 1800 cm/s), until December 31 of 2019. The Cox model was used to explore the association of TyG index and TG/HDL-C ratio with the arterial stiffness. Results During a mean follow-up of 5.09 years, 430 cases of arterial stiffness were confirmed. In the multivariate Cox model, the higher TyG index and TG/HDL-C ratio were positively associated with a higher risk of arterial stiffness (adjusted HR for per-unit increase: 1.39 and 1.08, P < 0.05). The adjusted HR (95% CI) comparing participants in the highest quartile versus lowest quartile of TyG and TG/HDL-C ratio were 1.51 (1.10–2.07) and 1.08 (1.01–1.15), respectively. This positive linear association of evaluated TyG index and TG/HDL-C ratio with arterial stiffness was confirmed using restricted cubic spline function. The observed association was stronger in subgroups with overweight, co-diabetes and poor blood pressure control (systolic pressure ≥ 140 mmHg or without anti-hypertension medication). Conclusion The elevated TyG index and TG/HDL-C ratio independently increased the future risk of arterial stiffness in hypertensive population. Monitoring TyG index and TG/HDL-C ratio deserves more attention in clinical practice, especially in the population with overweight, co-diabetes and poor blood pressure control.