[1] Seoul Natl Univ Hosp, Dept Internal Med, Seoul 110744, South Korea
[2] Kosin Univ, Gospel Hosp, Dept Internal Med, Pusan, South Korea
[3] Catholic Univ, Dept Internal Med, Seoul St Marys Hosp, Seoul, South Korea
[4] Yonsei Canc Ctr, Dept Internal Med, Seoul, South Korea
[5] Vet Hosp, Dept Internal Med, Seoul, South Korea
[6] Pusan Natl Univ Hosp, Dept Internal Med, Pusan, South Korea
[7] Keimyung Univ, Dept Internal Med, Dongsan Med Ctr, Taegu, South Korea
[8] Hallym Univ, Med Ctr, Dept Internal Med, Seoul, South Korea
[9] Natl Canc Ctr, Ctr Lung Canc, Ilsan, South Korea