The Relationships Among Skeletal Muscle Mass Index,Cardiorespiratory Fitness And The Prevalence Of Stable Coronary Artery Disease In The Elderly

OBJECTIVE:With the increase of the aging population,the prevalence of coronary heart disease is increasing year by year in China.Current research indicates that low muscle mass is an independent risk factor for coronary heart disease.Lower Cardiorespiratory fitness（CRF）are associated with risk of cardiovascular disease（CVD）events.skeletal muscle mass（SMM）loss and cardiorespiratory fitness（CRF）impairment are both independently associated with cardiovascular mortality in healthy adults.Therefore,we used elderly patients with stable coronary heart disease as the object to research the correlation between SMI,cardiorespiratory strength and stable coronary heart disease by cross-sectional study.METHODS:320 elderly inpatients who underwent coronary angiography or coronary CT angiography in the Department of Geriatrics,Second Affiliated Hospital of Chongqing Medical University were enrolled from March 2017 to January 2019.126 elderly patients who underwent coronary angiography or cardiac tomography and were diagnosed with SCAD were included in a SCAD group,and 194 patients without the diagnosis of coronary heart disease were included as controls.Collecting the general data of gender,age,smoking history,drinking history,blood pressure,BMI,etc.and taking fasting venous blood to measure serum fasting blood glucose concentration,glycosylated hemoglobin（HbAlc）,serum total cholesterol（TC）,triglyceride（TG）,Cardiovascular risk factors such as low density lipoprotein cholesterol（LDL-c）,serum creatinine（Scr）,uric acid（UA）,and hypersensitive C-reactive protein（hs-CRP）were compared to compare the differences between the SCAD group and the control group.The SMM index（SMI）was estimated using a bioelectrical impedance analyzer in the study.Cardiorespiratory exercise test（CPET）was used to assess CRF.This study used a multivariate logistic regression model to analyze the association between SMI and maximal oxygen uptake（VO₂ max）and SCAD,and used multiple linear regression to analyze the relationship between SMI and VO₂ max.RESULTS:（1）The prevalence of hypertension and diabetes,age,and Hemoglobin A1c levels in the SCAD group were significantly higher than those in the control group,and the difference was statistically significant（p<0.05）.The maximum metabolic equivalent,oxygen pulse,SMI and VO2 max in the SCAD group were significantly lower than those in the control group（p<0.05）.（2）In multivariate logistic regression analysis,after adjusting for traditional cardiovascular risk factors,hs-CRP（OR=2.043,95%CI=1.236-3.377,p=0.005）,DM（OR=3.394,95%CI=1.302-8.847,p=0.012）,VO₂ max（OR=0.035,95%CI=0.001-0.933,p=0.045）,SMI（OR=0.351,95%CI=0.245-0.503,p<0.001）are independently related to the prevalence of SCAD.（3）In linear regression analysis,VO₂ max（B=0.194,p=0.041）,MET max（B=0.249,p<0.001）,and VA（B=0.197,p<0.001）were associated with SMI.（4）The predictive value of VO₂ max and SMI for SCAD was analyzed by receiver operating characteristic（ROC）curve.The area under the ROC curve（AUC）was 0.758（95%CI:0.705-0.810,p<0.001）and 0.853,respectively.（95%CI:0.809-0.897,p<0.001）.Further analysis of the predictive value of SMI combined with VO₂ max for SCAD risk.The AUC was found to be 0.854 （95%CI:0.810-0.897,p<0.001）.It shows that when CRF and SMI are simultaneously predicted,the probability of predicting SCAD risk is stronger than that of CRF alone.CONCLUSIONS:Cardiorespiratory fitness（CRF）abnormalities are closely related to elderly stable coronary heart disease（SCAD）risk,which may be mediated by age-related reductions in SMM;when CRF is combined with skeletal muscle mass index（SMI）to predict SCAD risk,Its predictive value is significantly better than that of CRF and SMI alone,suggesting that early identification and intervention of muscle mass decline has important clinical value in reducing the risk of abnormal CRF-related SCAD.