RT Journal Article SR Electronic T1 Proton pump inhibitor or famotidine use and severe COVID-19 disease: a propensity score-matched territory-wide study JF Gut JO Gut FD BMJ Publishing Group Ltd and British Society of Gastroenterology SP 2012 OP 2013 DO 10.1136/gutjnl-2020-323668 VO 70 IS 10 A1 Zhou, Jiandong A1 Wang, Xiansong A1 Lee, Sharen A1 Wu, William Ka Kei A1 Cheung, Bernard Man Yung A1 Zhang, Qingpeng A1 Tse, Gary YR 2021 UL http://gut.bmj.com/content/70/10/2012.abstract AB