Diagnostic value of fractional exhaled nitric oxide in differentiating the asthma-COPD overlap from COPD: a systematic review and meta-analysis

Chuchu Zhangab, Meng Zhangab, Yalei Wangab, Xiaojie Suab, Ting Leiab, Haichuan Yuab & Jian Liua*a Department of Intensive Care Unit, Lanzhou University First Affiliated Hospital, Lan Zhou, Gansu Province, Chinab The First Clinical Medical College, Lanzhou University, Lanzhou, Gansu Province, China