1 Division of Pulmonology and Allergy, Department of Internal Medicine, Yeungnam University Medical Center, Youngman University College of Medicine, Daegu, Republic of Korea.
2 Department of Statistics and Actuarial Science, Soongsil University, Seoul, Republic of Korea.
3 Division of Pulmonary Medicine and Allergy, Department of Internal Medicine, Hanyang Medical Center, Hanyang University College of Medicine, Seoul, Republic of Korea.
4 Department of Family Medicine and Supportive Care Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
5 Supportive Care Center/Department of Family Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
6 Department of Clinical Research Design and Evaluation, Samsung Advanced Institute for Health Science and Technology (SAIHST), Sungkyunkwan University, Seoul, Republic of Korea.