“…This systematic review included 38 articles incorporating 5699 patients with severity outcomes and 6033 patients with mortality outcomes. Thirty-two articles were peer-reviewed [ 9 , [12] , [13] , [14] , [15] , [16] , [17] , [18] , [19] , [20] , [21] , [22] , [23] , [24] , [25] , [26] , [27] , [28] , [29] , [30] , [31] , [32] , [33] , [34] , [35] , [36] , [37] , [38] , [39] , [40] , [41] , [42] ], and six were preprints [ [43] , [44] , [45] , [46] , [47] , [48] ]; 23 articles compared NLR values on admission in severe vs. non-severe COVID-19 patients, 13 articles compared NLR values on admission in survivors vs. non-survivors of COVID-19, and only two articles compared the NLR values on admission in regard to both the severity and mortality of COVID-19 patients [ 21 , 47 ]. All the studies were retrospective observational studies, except for one which was prospective [ 33 ].…”