Abstract: BACKGROUND: The current prevention and control system of hypertension is facing the dilemma of "three lows" in awareness, treatment, and control rates; therefore, there is an urgent need to develop precise screening tools based on metabolic comprehensive indicators. The association between triglyceride-glucose-body mass index, as a novel biomarker of metabolic obesity, and the risk of hypertension in middle-aged and elderly Chinese population has not been fully validated.
OBJECTIVE: To validate the association between triglyceride-glucose-body mass index and the risk of hypertension in the middle-aged and elderly Chinese population based on the database of the China Health and Retirement Longitudinal Study (CHARLS).
METHODS: A total of 4 743 adults aged ≥ 45 years without hypertension were included. Using the quartile grouping method, the baseline triglyceride-glucose-body mass index was sorted in ascending order and divided into four equally sized intervals: the first quartile group (Q1, with the index < 170), the second quartile group (Q2, with the index between 170.38 and 191.176), the third quartile group (Q3, with the index between 191.179 and 216.82), and the fourth quartile group (Q4, with the index between 216.85 and 553.39). The Cox proportional hazards model was used to evaluate the association between triglyceride-glucose-body mass index and the risk of hypertension. Nonlinear relationships were identified using restricted cubic spline analysis, and robustness was validated through multiple sensitivity analysis.
RESULTS AND CONCLUSION: During the median follow-up period of 6.42 years, 1 975 hypertension patients were newly diagnosed, with an incidence rate of 648.80 cases per 10 000 person-year. For every 10 units increase in the triglyceride-glucose-body mass index, the risk of hypertension increased by 6% (hazard ratio: 1.06, 95% confidence interval [CI]: 1.05-1.08) in the first quartile group; the hazard ratios for the second quartile group, the third quartile group, and the fourth quartile group were 1.20 (95% CI: 1.02-1.40), 1.38 (95% CI: 1.17-1.62), and 1.97 (95% CI: 1.56-2.25), respectively. Using restricted cubic splines, a nonlinear correlation was identified between the triglyceride-glucose-body mass index and the risk of hypertension (P < 0.001), with an inflection point value of 146.1 (hazard ratio before the inflection point: 0.99, P > 0.05; and hazard ratio after the inflection point: 1.14, P < 0.001). The results showed that there was a significant positive correlation and nonlinear threshold effect between triglyceride-glucose-body mass index and the risk of hypertension in middle-aged and elderly population. It is recommended to use the triglyceride-glucose-body mass index < 146.1 as a cut-off point for preventing metabolic-related hypertension; therefore, the risk management of hypertension can be achieved through the control of weight, blood glucose and lipid.

Key words: triglyceride, glucose, body mass index, triglyceride-glucose-body mass index (TyG-BMI), hypertension, nonlinear correlation, insulin resistance, cardiovascular disease