Baseline data collected included APACHE II and bedside index for severity in AP (BISAP) within 24 hours of admission to our hospital. In addition, the occurrence of systemic inflammatory response syndrome (SIRS) was also recorded within the first week after admission. According to the Marshall multiple organ dysfunction scoring system, organ failure was defined as a score of ≥ 2 in 1 or more of 3 organs (respiratory, renal, and cardiovascular). The duration of organ failure included transient organ failure (≤ 48 hours) and persistent organ failure (> 48 hours).