Abstract: medRxiv preprint doi: https://doi.org/10.1101/2020.05.04.20089904; this version posted May 18, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-NC-ND 4.0 International license . Association of previous medications with the risk of COVID-19: a nationwide claimsbased study from South Korea Running title: Use of previous medications and COVID-19 in Korea Kyungmin Huh1¶, Wonjun Ji2¶, Minsun Kang3¶, Jinwook Hong3, Gi Hwan Bae3, Rugyeom Lee3, Yewon Na3, Hyoseon Choi4, Seon Yeong Gong4, Jaehun Jung3, 4* 1 Division of Infectious Diseases, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea 2 Department of Pulmonary and Critical Care Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea 3 Artificial Intelligence and Big-Data Convergence Center, Gil Medical Center, Gachon University College of Medicine, Incheon, Korea 4 Department of Preventive Medicine, Gachon University College of Medicine, Incheon, Korea ¶ KH, WJ, and MK contributed equally to this work. Keywords: COVID-19, drug repositioning, treatment, prophylaxis Running title: Use of various medications and COVID-19 Word count: 2,729 * Corresponding author: 1 NOTE: This preprint reports new research that has not been certified by peer review and should not be used to guide clinical practice. medRxiv preprint doi: https://doi.org/10.1101/2020.05.04.20089904; this version posted May 18, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-NC-ND 4.0 International license . Jaehun Jung, MD, PhD Department of Preventive Medicine, Gachon University College of Medicine 38-13, Dokjeom-ro 3, Incheon, Korea E-mail: eastside1st@gmail.com Abbreviations: ACE2, angiotensin-converting enzyme 2; ACEIs, ACE inhibitors; aOR, adjusted odds ratio; ARBs, angiotensin receptor blockers; CCI, Charlson comorbidity index; CI, confidence interval; COVID-19, coronavirus disease; CQ, chloroquine; HCQ, hydroxychloroquine; HIRA, Health Insurance Review & Assessment Service; ICD-10, International Classification of Diseases and Related Health Problems, 10th edition; OR, odds ratio; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2. 2 medRxiv preprint doi: https://doi.org/10.1101/2020.05.04.20089904; this version posted May 18, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-NC-ND 4.0 International license . Abstract Background. Identifying the association between medications taken prior to the infection of coronavirus disease (COVID-19) might be useful during the current pandemic until a proven treatment is developed. We aimed to determine whether the risk of developing COVID-19 was associated with the use of various drugs that may increase or decrease susceptibility to severe acute respiratory syndrome coronavirus 2 infection and COVID-19. Methods and Findings: A case-control study was performed using a nationwide claims database of South Korea, where a large testing capacity has been available throughout..