Abstract
Background/Objectives: Exercise capacity and patient prognosis are heavily influenced by comorbidities. However, the specific impact of individual comorbid conditions on objective measures of exercise performance remains insufficiently characterized. The study aimed to identify predictors of reduced physical capacity in patients qualified for cardiac rehabilitation. Methods: A single-center retrospective analysis was conducted on 518 patients qualified for cardiac rehabilitation. After excluding 51 post-cardiac surgery patients, cardiopulmonary exercise testing data from 425 patients (316 men, median age 63 years) were analyzed. Comorbidities data, peak oxygen uptake (peak VO(2)), and the ventilation-to-carbon dioxide output slope (VE/VCO(2) slope) were evaluated. Results: A significantly reduced exercise capacity (peak VO(2) < 70% of the predicted value) was observed in 29.4% of patients, while an increased VE/VCO(2) slope (≥36) was noted in 20.8% of patients. Univariate logistic regression identified sex, heart failure, valvular disease, peripheral artery disease, diabetes mellitus (T2DM), chronic kidney disease (CKD), Charlson Comorbidity Index (CCI), left ventricular ejection fraction <50%, diastolic dysfunction, and anemia as predictors of both reduced peak VO(2) and a steeper VE/VCO(2) slope. Multivariate regression analysis further identified T2DM and CKD as independent predictors of reduced peak VO(2), while sex, CKD, and CCI were independent predictors of a steeper VE/VCO(2) slope. Conclusions: Among patients qualified for cardiac rehabilitation, patient's sex, T2DM, CKD, and the CCI emerged as key predictors of reduced exercise capacity. Reduced peak VO(2) was more commonly observed in men, while women more frequently exhibited a steeper VE/VCO(2) slope, indicating potential sex-related physiological mechanisms influencing exercise performance.