Mets-IR as a Predictor of Cardiovascular Events in the Middle-Aged and Elderly Population and Mediator role of blood lipids
Authors: Qian Taoming , Sheng Xiaomeng , Shen Pengyu , Fang Yuting , Deng Yao , Zou Guoliang 
Published: May 2023

Background: Worldwide, cardiovascular disease has a high morbidity and mortality rate, and the number of cardiovascular fatalities in China is rising yearly. Using fasting glucose, fasting triglycerides, body mass index (BMI), and high-density lipoprotein cholesterol (HDL-C), the metabolic score of insulin resistance (Mets-IR), a novel index created by Mexican researchers to assess insulin sensitivity, is a more precise way to measure insulin sensitivity. This study sought to determine the mediating function of triglycerides in the link between insulin resistance and cardiovascular disease, stroke, and cardiac issues in a Chinese population.
Methods: The study's data came from the 2011 and 2018 China Health and Retirement Longitudinal Studies (CHARLS). We used three logistic regression models to account for the potential effects of ten factors on cardiovascular disease/stroke/heart disease (age, gender, marital status, education level, location, smoking status, drinking status, sleep duration, lipid level, blood glucose level, and past medical history). In order to determine the involvement of triglycerides (TG) in the link between Mets-IR and cardiovascular disease/stroke/heart disease events, we also conducted a mediation analysis using the R package "Mediation". Finally, we made an effort to fit Mets-IR into a logistic regression model to see if it has any more predictive power than already-established clinical risk factors.
Results: This study comprised 4540 participants, of whom 494 (10.88%) were found to have cardiovascular disease (CVD). According to the data, participants with CVD had significantly higher triglyceride levels and baseline ages as well as shorter sleep duration. Moreover, the prevalence of CVD was greater in men than in women (p=0.03). The last Mets-IR quartile (Q4) had the highest risk of new-onset cardiovascular disease, according to analysis using Mets-IR as a continuous variable (OR=1.81, 95CI=1.37-2.38) and there was a linear dose-response relationship between Mets-IR and the risk of new-onset cardiovascular disease, stroke, and heart issues (Poverall<0.05, Pnon-linear>0.05). No significant interactions between socioeconomic traits and medical history and Mets-IR were revealed by stratified analysis. Approximately 2.5% and 3.5% (indirect effect/total effect) of the significant correlations of Mets-IR with cardiovascular events and stroke were mediated by TG, respectively. With the addition of Mets-IR to the base model, the continuous NRI and IDI for predicting cardiovascular disease increased by 0.175 (P <0.001) and 0.006 (P <0.001), respectively, showing a significant improvement in the incremental prediction analysis of Mets-IR.
Conclusion: Mets-IR is linked to an increased risk of cardiovascular disease/stroke/cardiac issues, and TG mediates these connections. Improving insulin sensitivity and lipid regulation may be essential and effective preventive measures for cardiovascular events.