Associations of the Triglyceride and Glucose Index with Hypertension Stages, Phenotypes, and Progressions among Middle-aged and Older Chinese

Background The triglyceride and glucose (TyG) index has been proposed as a surrogate indicator of insulin resistance. By far, the associations of the TyG index with hypertension stages, phenotypes, and progressions remain unclear. Methods The data originated from two waves (2011 and 2015) of the China Health and Retirement Longitudinal Study (CHARLS). Participants with systolic blood pressure ≥ 140 mmHg and/or diastolic blood pressure ≥ 90 mmHg and/or using antihypertensive medications were considered hypertensive. After excluding those under antihypertensive medications, hypertension stages were classified as stage 1 and stage 2, and phenotypes were classified as isolated systolic hypertension (ISH), isolated diastolic hypertension (IDH), and systolic diastolic hypertension (SDH). Multinomial logistic regression was used to investigate the associations of the TyG index with hypertension stages and phenotypes, together with their progressions from 2011 to 2015. Results At baseline in CHARLS 2011, a total of 8,209 participants were recruited, among whom 3,169 (38.6%) were hypertension. Compared with individuals with the lowest quartile (Q1) of TyG index, those with the highest quartile (Q4) were significantly associated with increased risks of stage 1 hypertension (odds ratio [OR] 1.71, 95% confidence interval [CI] 1.38-2.13), stage 2 hypertension (1.74, 1.27-2.38), ISH (1.66, 1.31-2.11), IDH (2.52, 1.26-5.05), and SDH (1.65, 1.23-2.23). Similar results were found when the TyG index was used as a continuous variable. From 2011 to 2015, a higher baseline TyG index was revealed to be significantly associated with the progressions from normotension to stage 1 (for Q4 vs Q1: 1.45, 1.05-2.00; for per-unit: 1.39, 1.16-1.65), normotension to ISH (for per-unit: 1.28, 1.04-1.56), and normotension to IDH (for Q4 vs Q1: 3.46, 1.42-8.44; for per-unit: 1.94, 1.27-2.97). Conclusions The TyG index was significantly associated with different hypertension stages, phenotypes and their progressions. Our findings highlight the importance of the TyG index as a potential surrogate indicator for early hypertension screening and management.