[1] Sun Yat Sen Univ, Dept Pulm Med, Affiliated Hosp 1, Guangzhou 510080, Guangdong, Peoples R China
[2] Meizhou City Peoples Hosp, Dept Pulm Med, Meizhou 51000, Guangdong, Peoples R China
[3] Sun Yat Sen Univ, Affiliated Hosp 3, Dept Pulm Med, Guangzhou 510000, Guangdong, Peoples R China