1. Department of Respiratory and Critical Care Medicine, Zhengzhou University People’s Hospital, Henan Provincial People’s Hospital, Zhengzhou, Henan 450003, China
2. Department of Internal Medicine, Academy of Medical Science, Zhengzhou University, Zhengzhou, Henan 450001, China
3. Department of Internal Medicine, Xinxiang Medical University, Xinxiang, Henan 453003, China