1. Department of Family Medicine, Yongin Severance Hospital, Yonsei University College of Medicine, Yongin 16995, Republic of Korea
2. Primary Care Research Center, National Health Insurance Service, Ilsan Hospital, Goyang 10326, Republic of Korea
3. Department of Family Medicine, Nowon Eulji Medical Center, Eulji University School of Medicine, Seoul 01830, Republic of Korea
4. Department of Medicine, School of Medicine, Hanyang University, Seoul 04763, Republic of Korea