Triglyceride-glucose index and abnormal blood pressure in adults aged over 70 years: real-world data evidence

Existing studies on the association between the triglyceride-glucose index (TyG) and hypertension often rely on simplified hypertension classifications and provide limited evidence specific to the elderly population (aged ≥ 70 years). This study aims to explore the relationship between the TyG index and different subtypes of abnormal blood pressure in older adults. A cross-sectional study was conducted in 2022 using random cluster sampling, including 12,690 permanent residents aged ≥ 70 years from rural communities. Blood pressure was measured by uniformly trained staff using calibrated electronic sphygmomanometers under resting conditions. The triglyceride-glucose (TyG) index was analyzed both as a continuous variable and in quartiles. Multivariable logistic regression models, adjusted for age, sex, education level, marriage, smoking, alcohol consumption, family history of diabetes, family history of hypertension, heart rate, and body mass index, were used to assess the associations between the TyG index and hypertension subtypes. The discriminatory ability of the TyG index was evaluated using receiver operating characteristic (ROC) curve analysis, with adjustment for the same set of covariates. The overall crude prevalence of hypertension (HTN) was 55.9%. The prevalence rates of systolic hypertension (SHTN), grade 1 hypertension (HTN-I), and grade 2 hypertension (HTN-II) were 37.6%, 37.5%, and 18.3%, respectively. Participants in the highest TyG index quartile had a significantly increased risk of all hypertension subtypes compared to those in the lowest quartile. Trend analysis showed that each 1-unit increase in the TyG index was associated with increased risks of HTN (OR = 1.39, 95% CI: 1.18–1.63), SHTN (OR = 1.33, 95% CI: 1.11–1.60), HTN-I (OR = 1.30, 95% CI: 1.09–1.55), and HTN-II (OR = 1.52, 95% CI: 1.22–1.89) (P for trend < 0.01). ROC curve analysis determined optimal TyG cutoff values for predicting HTN (8.96), SHTN (8.96), HTN-I (8.96), and HTN-II (9.11), but modest discriminatory ability of the TyG index for these abnormal blood pressure subtypes (all P < 0.001), with areas under the curves (AUCs) ranging from 0.56 to 0.58. An elevated TyG index is independently associated with abnormal blood pressure in the elderly, with a particularly strong association observed for HTN-II. Although its discriminatory power as a standalone diagnostic tool is limited, the index may serve as a useful auxiliary factor for hypertension risk assessment in this population.