Combination of triglyceride-glucose index and waist-to-height ratio as a predictor of all-cause and cardiovascular mortality in adults with diabetes or prediabetes: a nationwide prospective cohort study.

Abstract

Background: Insulin resistance (IR) and central obesity play a crucial role in the pathogenesis of metabolic diseases. However, the association between the triglyceride-glucose index combined with waist-to-height ratio (TyG-WHtR)-a novel proxy for both insulin resistance and central obesity-and mortality outcomes in adults with prediabetes and diabetes remains unclear. The aim of this study is to explore the association between TyG-WHtR and all-cause and cardiovascular (CVD) mortality in prediabetic and diabetic adults.

Methods: The study enrolled 19,563 United States (U.S.) adults diagnosed with prediabetes or diabetes from the National Health and Nutrition Examination Survey (NHANES). Data were collected in eight continuous 2-year cycles from January 2003 to December 2018. The Kaplan-Meier curve, Cox proportional risk model, restricted cubic spline (RCS) curve, and subgroup analysis were used to evaluate the association of the TyG-WHtR index with all-cause mortality and CVD-related mortality in US adults with prediabetes and diabetes. A series of sensitivity analyses were performed to test the robustness of the findings.

Results: After a median follow-up of 7.6 years, 2,949 all-cause deaths were recorded (15.1% death rate over the follow-up period), of which 969 (32.86%) were CVD related. Multivariate adjustment models showed a gradual increase in all-cause mortality and CVD-related mortality with each increasing TyG-WHtR index quartile. Specifically, for every one unit increase in TyG-WHtR, the risk of all-cause death increased by 19% [hazard ratio (HR) =1.19, 95% confidence interval (CI): 1.1-1.28; P<0.001] and there was also an associated 11% increased risk of death from CVD, although this did not reach statistical significance (HR =1.11, 95% CI: 0.98-1.27; P=0.11). Compared with patients in the lowest quartile (Q1), those in the highest quartile (Q4) had an all-cause mortality HR of 1.39 (95% CI: 1.06-1.81) and a CVD-related mortality HR of 1.36 (95% CI: 0.91-2.03). Interaction tests revealed significant effect modification by body mass index (BMI) (all-cause mortality) and family income-to-poverty ratio (CVD-related mortality).

Conclusions: In a sample of US adults with prediabetes and diabetes, we found an association between TyG-WHtR index and both all-case and CVD-related mortality. The TyG-WHtR index could serve as an alternative biomarker for the clinical management of patients with prediabetes and diabetes.