Comorbidity burden outweighs coronary heart disease diagnosis in impairing cardiopulmonary fitness: a cross-sectional study based on cardiopulmonary exercise testing
摘要
Multimorbidity was highly prevalent in patients with coronary heart disease (CHD), yet its independent and cumulative impact on cardiorespiratory fitness (CRF) remains incompletely elucidated. This cross-sectional study analyzed the respective effects of comorbidity burden and CHD diagnosis on peak oxygen uptake (VO₂peak) and examined whether obesity modulated the comorbidity–CRF relationship.
MethodsA total of 335 adults undergoing symptom-limited cardiopulmonary exercise testing at Fuzhou University Affiliated Provincial Hospital were enrolled (CHD group: n = 156; non-CHD group: n = 179). Multiple linear regression models assessed the independent and interactive effects of CHD diagnosis, comorbidity count, and body mass index (BMI) on VO₂peak.
ResultsDespite older age (63 vs. 53 years, P < 0.001) and a higher comorbidity burden (P < 0.001) in the CHD group, VO₂peak did not differ significantly between the two groups (20.33 vs. 20.88 mL/kg/min, P = 0.234). CHD diagnosis was not a statistically significant predictor of VO₂peak (β=−0.415, P = 0.386), whereas comorbidity count exhibited a dose–response relationship (β=−0.824, P < 0.001), with each additional comorbidity reducing VO₂peak by 0.82 mL/kg/min. As comorbidities increased from 0 to ≥ 3, VO₂peak declined from 21.19 to 19.58 mL/kg/min (P for trend = 0.004), accompanied by parallel deteriorations in oxygen uptake at the anaerobic threshold, oxygen uptake efficiency slope, and ventilatory efficiency. Although the linear interaction term between BMI and comorbidity was non-significant (P = 0.469), stratified analyses confirmed consistent negative trends across all groups, with the overweight group (BMI 24–28 kg/m²) exhibiting a numerically steeper downward trajectory.
ConclusionsComorbidity burden outweighed CHD diagnosis per se as the primary driver of CRF impairment, with cumulative effects exhibiting a dose–response relationship. Our findings suggest that the detrimental impact of multimorbidity is robust across different weight statuses. Although a steeper decline was visually observed in the overweight group, further large-scale studies are needed to verify whether specific BMI ranges confer heightened sensitivity.