Association between metabolic score for insulin resistance and risk of cardiometabolic multimorbidity: an analysis based on two national prospective cohorts

Cardiometabolic multimorbidity (CMM) has become a major global health concern, carrying substantial mortality risk. This study investigated the association between the metabolic score for insulin resistance (METS-IR) and the incidence of CMM. This prospective analysis utilized data from two nationally representative cohorts (CHARLS and ELSA). The association between the baseline METS-IR and incident CMM was assessed using logistic regression models. Restricted cubic splines and subgroup analyses were employed to examine the relationship pattern and consistency. In the follow-up period, there were 149 cases of CMM in CHARLS and 287 cases in ELSA. Every unit increase in METS-IR correlated with a 4% elevated risk of CMM in both groups. Individuals in the highest METS-IR quartile exhibited a more than threefold elevation in CMM risk compared with those in the lowest quartile. A linear dose–response relationship was identified, exhibiting similar relationships across the majority of categories, albeit influenced by hypertension and chronic lung disease status. In CHARLS and ELSA, elevated baseline METS-IR independently predicted higher incident CMM risk in midlife and older adults, with a linear dose–response. As a routine-test-based metric, METS-IR can support early high-risk screening for targeted prevention.