“…The discrepancy in the number of subjects between trials were large and it varied from 25 to 3298. The subjects were from medical ICU [7,25,26,30,31,38,40], surgical ICU [8,10,13,28,34,35,37,39,41,44], or both [9,11,12,18,24,27,29,32,33,36,42,43] [8,24,30,33,36,43], and it is worth mentioning that the trial by Gursoy et al [33] set 5 intervention groups and one control group, all intervention groups received PPI, hence we combined the intervention groups into a single group to compare with the control group. Notably, the trials by Kantorova et al [35] and Liu et al [37] set 2 intervention groups in which one group used PPI and another group used H2RA, therefore the control group was divided evenly into two groups to make two comparisons.…”