“…Methods for determining the baseline serum creatinine (sCr) varied across studies, with some using the first sCr measured within 3 days of ICU admission [14,19 ▪▪ ,27,29,31,34] and others using the lowest value during ICU admission [5 ▪▪ ,9,18]. Studies also established baseline sCr from the lowest sCr prior to admission (ranging from 365 days to 1 week prior [25 ▪▪ ,29,30,32 ▪▪ ] or within 7 days prior [24]), mean sCr from 180 to 7 days prior to admission [21 ▪▪ ,26 ▪ ], preoperative sCr [6,31] or the Modified Diet and Renal Disease (MDRD) equation if a measured sCr was not available [9,12,26 ▪ ,30]. Eleven studies did not define baseline sCr [7 ▪▪ ,10 ▪▪ ,11–13,15,20 ▪▪ ,22 ▪▪ ,23 ▪ ,28,33].…”