Middle-aged and older populations with different subtypes and definitions of metabolic syndrome face different future cardiovascular disease risks: results from a comparison of two Chinese definitions

Abstract Background Differences in the association between metabolic syndrome (MetS) and cardiovascular disease (CVD) across definitions and subtypes are unknown. The aim of this study was to investigate the differences between the associations of MetS defined by the Chinese Diabetes Society (CDS) and the Writing Group of 2024 Chinese Guidelines for the Management of Hypertension (WCGH) with CVD. Methods This cohort study included participants aged ≥ 40 years without cardiovascular disease from the 2011 survey of the China Health and Retirement Longitudinal Study. Individuals meeting different definitions of MetS based on criteria from the CDS and the WCGH were identified and followed up until 2020. Cox proportional risk models were used to analyze the association between different definitions and subtypes of MetS with CVD, and the predictive performance of the models was compared using the area under the curve (AUC) of the time-dependent receiver operating characteristic curve, integrated discrimination improvement (IDI), and net reclassification improvement (NRI). Results Both CDS and WCGH based MetS were significantly associated with increased CVD risk, with hazard ratios (HRs) and 95% confidence intervals (CIs) of 1.51 (1.38 ~ 1.66) and 1.81 (1.66 ~ 1.99), respectively, both P < 0.001. 7 of the 16 subtypes of MetS based on CDS were not associated with CVD; all 5 subtypes of MetS based on WCGH were significantly associated with an increased risk of CVD. When participants were grouped based on meeting two definitions, compared with the CDS-WCGH- group, CVD risk increased most significantly in the CDS-WCGH + group (HR and 95%CI: 2.57 [1.94 ~ 3.39], P < 0.001), showed a significant increase in the CDS + WCGH + group (HR and 95%CI: 1.66 [1.51 ~ 1.83], P < 0.001), and showed no significant increase in the CDS + WCGH- group (HR and 95%CI: 0.93 [0.7 ~ 1.23], P = 0.606). The AUC of WCGH was higher than that of CDS at all time points. IDI and NRI analyses showed that the WCGH standard demonstrated significant improvements in risk reclassification and identification compared to CDS. Conclusions The association between MetS and CVD depends on the definition criteria and specific component combinations employed. The WCGH definition, which integrates diagnostic criteria for dyslipidemia, has been demonstrated to be more robust than the CDS. Graphical abstract