Triglyceride-glucose index and the progression of chronic obstructive pulmonary disease, panvascular disease, and multimorbidity: a prospective cohort study - Shuo Zhang; Xiaotian Li; Jiajing Li; Siwei Xie; Zongbin Wang; Zhijie Zheng; Jie Huang; Shuduo Zhou (Frontiers in Cardiovascular Medicine, 2026)