The association between baseline and long-term status of metabolic score for insulin resistance index and the incidence of cardiometabolic multimorbidity

Background: Cardiometabolic multimorbidity (CMM) is concurrently associated with a reduction in life expectancy and an increased propensity for all-cause mortality. Our objective was to evaluate the correlations between the baseline and longitudinal metabolic score for insulin resistance index (METS-IR) and the incidence of cardiometabolic multimorbidity (CMM) within a middle-aged and older Chinese population cohort.. Methods and Results: A total of 8,050 participants were enrolled and included in the analytical dataset for this study. Long-term status of METS-IR were defined as updated mean METS-IR and high METS-IR exposure duration. Updated mean METS-IR was defined as the mean of the two METS-IR measurements. High METS-IR exposure duration was defined as the times of visits with a high METS-IR among the 2 visits, quantified as 0 year, 2 years and 4 years according to the optimal cut points from the receiver operating characteristic curves of the two METS-IR measurements, respectively. The outcome was defined as the occurrence of CMM, characterized by the presence of two or more cardiometabolic disorders as self-reported by participants, encompassing conditions such as diabetes, stroke, and cardiac events. During 6-year visit, 540 participants experienced CMM. Substantially elevated incidences of CMM were observed in participants belonging to the highest tertiles of both baseline and updated mean METS-IR. After multivariable adjustment, the odds ratios (ORs) with 95% confidence intervals (CIs) for CMM were 2.94 (CI: 2.04-4.22) for those in the highest baseline METS-IR tertile and 3.26 (CI: 1.90-5.59) for those in the highest updated mean METS-IR tertile, relative to participants in the lowest tertiles. Multivariable-adjusted spline regression models showed a linear association of baseline METS-IR ( P _linearity <0.0001) and updated mean METS-IR ( P _linearity <0.0001) with CMM. Moreover, participants with 2 and 4 years high METS-IR exposure duration had increased risk of CMM (ORs [95% CIs]: 2.45 [1.52-3.96] and 3.46 [2.18-5.51], respectively), compared with the reference of those with unexposed group. Conclusion: This study proved elevated baseline METS-IR, updated mean METS-IR, especially high METS-IR exposure duration was associated with CMM incidence among middle-aged and older Chinese.