Association between body mass index and cardiopulmonary function in patients with chronic coronary syndrome

Background: Patients with chronic coronary syndrome (CCS) are frequently complicated by reduced exercise tolerance. Previous studies exploring the relationship between body mass index (BMI) and cardiopulmonary function among CCS patients have reported conflicting results, and the definite association between the two indicators remains unclear. Accordingly, we performed this study to characterize their actual correlation.Methods: This retrospective study examined the association between BMI and Cardiopulmonary Exercise Testing (CPET) indices and the modifying effect of sex in 405 CCS patients recruited from the Cardiovascular Disease Center of Taizhou People’s Hospital. Patients were divided into three groups based on BMI tertiles, and CPET parameters were compared. Multiple linear regression and sex-stratified analyses were conducted.Results: In patients with CCS, BMI exerted a bidirectional linear differential effect on cardiopulmonary exercise capacity without nonlinear inflection points: higher BMI correlated with greater PeakVO2 (B = 22.851, 95%CI: 16.180–29.522, β = 0.270, p < 0.001), yet lower Peak VO2/kg (B=-0.214, 95%CI: −0.310–-0.117, β=-0.212, p < 0.001). This association was modified by sex. The positive association between BMI and PeakVO2 was stronger in males (B = 31.708, 95%CI: 21.609–41.806, β = 0.377, p < 0.001), whereas the negative inhibitory effect of BMI on Peak VO2/kg was more pronounced in females (B=-0.242, 95%CI: −0.370–-0.115, β=-0.271, p < 0.001). Moreover, other determinants of cardiopulmonary function exhibited sex disparities.Conclusion: In patients with CCS, higher BMI was positively correlated with absolute peak exercise capacity but negatively correlated with peak VO2/kg, and this correlation showed sex heterogeneity.