[1] Chonnam Natl Univ, Internal Med, Gwangju, South Korea
[2] Masan Natl TB Hosp, Chest Med, Changwon Si, South Korea
[3] Pusan Natl Univ, Yangsan Hosp, Yangsan, South Korea
[4] Seoul Natl Univ, Coll Med, Dept Internal Med, Seoul, South Korea
[5] Asan Med Ctr, Seoul, South Korea