The association between cardiovascular diseases and their subcategories with the severity of chronic obstructive pulmonary disease: a large cross-sectional study based on a Chinese hospital population cohort - Li, Tianye; Chen, Lefu; Xu, Hao; Zheng, Yanhong; Yang, Heying; Zhao, Hongjun; Chen, Chengshui (Frontiers in Cardiovascular Medicine, 2025)