Impact of anthropometric parameters in patients with chronic coronary syndromes: insights from the CLARIFY registry

Background The prognostic impact of body size on outcomes in patients with chronic coronary syndromes (CCS) remains incompletely understood. Various measurements exist to differentiate between central and peripheral adiposity, with strong evidence suggesting that central adiposity represents the most adverse phenotype for cardiovascular (CV) risk. Purpose To evaluate the prognostic impact of baseline anthropometric parameters in a large, international registry of patients with CCS. Methods The international CLARIFY registry enrolled over 32,000 outpatients with CCS across 32 countries. This analysis included patients with available baseline anthropometric measurements. Evaluated parameters included weight, body mass index (BMI), waist circumference (WC), WC/BMI ratio, and WC/height ratio. The primary outcome was a composite of CV death and myocardial infarction (MI) at 5-year follow-up. Restricted cubic splines (RCS) were plotted to assess relationships between continuous anthropometric variables and the primary outcome. Results were adjusted for known predictors of adverse events in the CCS population. Results A total of 31,782 patients were included. Mean weight was 79.5±15.2 kg, mean BMI was 27.9±4.5 kg/m2, and mean WC was 97.5±12.8 cm. The mean WC/BMI ratio was 3.5±0.4, and the mean WC/height ratio was 0.58±0.07. At 5-year follow-up, 2259 (7.1%) patients experienced the primary outcome. RCS analysis revealed a U-shaped relationship between weight or BMI and CV outcomes, with the nadir of CV risk observed at a BMI of 29.2 kg/m2. The relationship between WC or WC/height ratio and CV outcomes followed a J-curve, characterized by a linear increase in adverse events above a WC of 110 cm or a WC/height ratio of 0.7. Conversely, the WC/BMI ratio demonstrated a strict linear increase in risk for the primary outcome (aHR 1.30 per unit increase, 95%CI 1.15-1.47, p<0.001). Given this linear association, WC/BMI was further explored in specific subgroups. It remained independently associated with 5-year CV events in most subgroups, though not in the youngest and most physically active patients. To confirm that central adiposity drives risk independently of general obesity, BMI categories and the WC/BMI ratio were analyzed in a combined Cox model. No significant collinearity was observed; the WC/BMI ratio maintained its independent linear predictive value, while the U-shaped association persisted for BMI. Analysis of all-cause mortality yielded consistent findings. Conclusion While BMI exhibits a U-shaped relationship with CV outcomes in patients with CCS, the WC/BMI ratio demonstrates a strict, linear increase in 5-year risk. This contrast highlights that central adiposity relative to total body mass is an independent driver of adverse outcomes, strongly supporting the routine incorporation of the WC/BMI ratio to refine clinical risk stratification.