Potential risk factors
Based on previous reports (Boettler et al., 2020; Chen et al., 2020; Jordan et al., 2020; Klonoff et al., 2020; Leung, 2020; Li et al., 2020; Liu et al., 2020; Long et al., 2020; Mehra et al., 2020; Wang et al., 2020; Zhang et al., 2020; Zheng et al., 2020; Zheng et al., 2020; Zhou et al., 2020), several risk factors were selected for analysis as possible confounding variables. These risk factors included age, sex, body weight, comorbidities (hypertension, diabetes, cardiovascular disease, respiratory system disease, past surgical history), liver function (ALT, AST), and renal function (BUN and creatinine).