Supplementary Material for: From Renal Markers to Muscle Mass: A Sarcopenia Index Predicts Outcomes in Coronary Artery Disease Patients with Aortic Valve Sclerosis

Background: Renal function plays a pivotal role in influencing various diseases, particularly cardiovascular conditions. Renal markers show strong associations with coronary artery disease (CAD), aortic valve sclerosis (AVSc), and sarcopenia. The Sarcopenia Index (SI), a biomarker derived from renal markers, serves a dual purpose: it precisely quantifies muscle mass while also acting as a prognostic indicator for adverse cardiovascular outcomes, especially in patients with concurrent CAD and AVSc.
Methods: A retrospective analysis was performed on consecutive CAD patients treated from 2013 to 2014. The SI was calculated using the formula [serum creatinine (mg/dL)/cystatin C (mg/dL)] × 100. The primary composite endpoint was cardiovascular death or rehospitalization for heart failure or acute coronary syndrome events. The secondary endpoint included the primary endpoint plus all-cause mortality. Kaplan-Meier analysis, and Cox proportional hazards modeling was applied to analyze the association between SI and outcomes
Results: Among the 1,123 CAD patients, 277 had AVSc. Patients with AVSc had significantly lower SI, which was independently associated with AVSc presence (OR=1.750, P<0.001). Associations between SI and both endpoints were identified in CAD patients with AVSc rather than in those without AVSc. SI below the median (89.40) was predictive of worse outcomes. Lower SI significantly increased the risk for the primary (HR=1.883, P=0.035) and secondary (HR=1.910, P=0.021) endpoints in AVSc subgroup.
Conclusion: Lower SI is independently associated with AVSc in CAD patients and was also associated with adverse cardiovascular events and mortality in CAD patients with AVSc.