Association between metabolic score for insulin resistance and hypertension in middle-aged and older adults: a nationwide cross-sectional and longitudinal study

Abstract

Introduction: Metabolic score for insulin resistance (METS-IR) is a promising and reliable non-insulin-based method for assessing insulin resistance and cardiovascular disease risk. Through cross-sectional and longitudinal analyses, we evaluated the predictive ability of METS-IR for hypertension risk, aiming to provide a basis for early screening and intervention strategies to reduce hypertension-related complications. Methods: Data were utilized from the China Health and Retirement Longitudinal Study (CHARLS), involving participants aged 45 and above with complete METS-IR and self-reported hypertension records. A combination of cross-sectional (waves 1 and 3) and longitudinal designs was used to track hypertension incidence, with 10,738 participants in the cross-sectional analysis and 6,788 participants in the longitudinal analysis. Data collection included health behaviors, physical measurements, and blood tests. METS-IR was calculated using a standardized formula, and hypertension was defined according to established criteria. Statistical analyses assessed associations, with a significance level set at p < 0.05. Results: The cross-sectional analysis, after adjusting for confounders, showed that each unit increase in METS-IR was associated with a threefold increase in the risk of hypertension (adjusted OR = 3.48, 95% CI: 2.87, 4.21, P < 0.0001). A significant nonlinear relationship between METS-IR and hypertension risk was observed, particularly beyond a value of 2.0, where the risk significantly increased. Subgroup analysis revealed that smoking and sex significantly affected this association. Longitudinal analysis demonstrated that each unit increase in METS-IR was significantly associated with increased hypertension incidence at 2 years (OR = 1.54, 95% CI: 1.09, 2.18, P < 0.05), 5 years (OR = 1.52, 95% CI: 1.17, 1.97, P < 0.05), and 7 years (OR = 1.71, 95% CI: 1.38, 2.12,, P < 0.0001), respectively. Conclusion: Using CHARLS data, we found that higher METS-IR independently predicts hypertension incidence and prevalence in Chinese older adults.