Association between metabolic syndrome severity score and coronary artery disease complexity assessed by the SYNTAX score in patients with chronic coronary syndrome

Background Metabolic syndrome represents a cluster of interrelated cardiometabolic abnormalities associated with coronary artery disease. However, conventional definitions evaluate metabolic syndrome categorically and may not adequately reflect its cumulative severity. The primary objective of this study was to assess whether the metabolic syndrome severity Z-score (MetS-Sz) was independently associated with coronary artery disease complexity, as quantified by the SYNTAX score, in patients with chronic coronary syndrome. Methods This single-center retrospective cross-sectional study included 156 patients with chronic coronary syndrome who underwent coronary angiography. MetS-Sz was calculated using age-, sex-, race-, and body mass index-based metabolic variables, whereas coronary lesion complexity was assessed using the SYNTAX score. Participants were categorized into lower (MetS-Sz < 0) and higher (MetS-Sz ≥ 0) MetS-Sz groups, corresponding to values below and at or above the reference population mean. Clinical, anthropometric, and biochemical characteristics were compared between groups. Correlation analysis and multiple linear regression were performed to evaluate the association between MetS-Sz and the SYNTAX score. Results Of the 156 participants, 123 (78.8%) were men and 33 (21.2%) were women. Patients in the higher MetS-Sz group had significantly higher body mass index, triglyceride, total cholesterol, low-density lipoprotein cholesterol, glucose, diastolic blood pressure, and SYNTAX scores and lower high-density lipoprotein cholesterol levels than those in the lower MetS-Sz group (all p < 0.05). MetS-Sz was positively correlated with the SYNTAX score ( r s = 0.675, p < 0.001). The multiple linear regression model was statistically significant ( F = 22.84, p < 0.001) and explained 51.9% of the variance in the SYNTAX score (R 2 = 0.519). MetS-Sz, low-density lipoprotein cholesterol, body mass index, triglyceride level, and smoking status were independently associated with the SYNTAX score, whereas diabetes and diastolic blood pressure were not significantly associated with it. Conclusions Higher MetS-Sz was independently associated with greater coronary artery disease complexity in patients with chronic coronary syndrome. These findings suggest that assessment of cumulative metabolic burden using MetS-Sz may complement conventional cardiovascular risk evaluation. Prospective, multicenter studies are required to confirm its potential role in coronary risk stratification.