title: Prevention effect of allopurinol on post-endoscopic retrograde cholangiopancreatography pancreatitis: a meta-analysis of prospective randomized controlled trials.
abstract: BACKGROUND
  Pancreatitis is the most common complication of endoscopic retrograde cholangiopancreatography (ERCP) which can be severe and cause death in approximately 10% of cases. Up to now, six randomized controlled trials (RCTs) have been found relevant to the effect of allopurinol on prevention of Post-ERCP pancreatitis (PEP). However, these results remained controversial.
  
  
  OBJECTIVE
  To conduct a meta-analysis with RCTs published in full text to determine the effectiveness of prophylactic allopurinol of different dosages and administration time in the incidence and severity of PEP.
  
  
  METHODS
  Literature search was performed in PubMed, Embase, Web of Science and Cochrane Library from databases inception to May 2014. RCTs comparing the effect of allopurinol with placebo on prevention of PEP were included. Statistical heterogeneity was quantitatively evaluated byχ2 test with the significance set P<0.10 or I2>50%.
  
  
  RESULTS
  Six RCTs consisting of 1974 participants were eventually included. The incidences of PEP in allopurinol group and placebo group were 8.4%(83/986) and 9.9%(98/988) respectively. Meta-analysis showed no evident prevention effect of allopurinol on the incidence of PEP (RR 0.75, 95%CI 0.39-1.42) with significant heterogeneity (I2 = 70.4%, P = 0.005). When studies were stratified according to the dosages and administration time of allopurinol they applied, there was still no evident prevention effect of allopurinol on mild, moderate or severe PEP. However, statistically substantial heterogeneity was presented in the subgroup of moderate PEP when the effect of high dose of allopurinol was analyzed (Imoderate2 = 82.3%, Pmoderate = 0.018). Statistically significant heterogeneity was also observed in subgroup of mild PEP, when the effect of long adminstration time of allopurinol was investigated (Imild2 = 62.8%, Pmild = 0.068).
  
  
  CONCLUSIONS
  The prophylactic use of allopurinol in different dosages and administration time had no effect in preventing incidence and severity of PEP.
authors.affiliation: Postgraduate Training Base, Affiliated Hospital of Logistics University of the Chinese People's Armed Police Forces, Liaoning Medical University, Jinzhou, China; Department of Hepatopancreatobiliary and Splenic Medicine, Affiliated Hospital of Logistics University of the Chinese People's Armed Police Forces, Tianjin, China.
authors.forename: Wei-Li
authors.initials: WL
authors.lastname: Cao
authors.affiliation: Postgraduate Training Base, Affiliated Hospital of Logistics University of the Chinese People's Armed Police Forces, Liaoning Medical University, Jinzhou, China; Department of Endemic Area of Orthopedic Center Section III, Affiliated Hospital of Logistics University of the Chinese People's Armed Police Forces, Tianjin, China.
authors.forename: Wen-Shan
authors.initials: WS
authors.lastname: Yan
authors.affiliation: Department of Hepatopancreatobiliary and Splenic Medicine, Affiliated Hospital of Logistics University of the Chinese People's Armed Police Forces, Tianjin, China.
authors.forename: Xiao-Hui
authors.initials: XH
authors.lastname: Xiang
authors.affiliation: Department of Hepatopancreatobiliary and Splenic Medicine, Affiliated Hospital of Logistics University of the Chinese People's Armed Police Forces, Tianjin, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Chen
authors.affiliation: Postgraduate Training Base, Affiliated Hospital of Logistics University of the Chinese People's Armed Police Forces, Liaoning Medical University, Jinzhou, China; Department of Hepatopancreatobiliary and Splenic Medicine, Affiliated Hospital of Logistics University of the Chinese People's Armed Police Forces, Tianjin, China.
authors.forename: Shi-Hai
authors.initials: SH
authors.lastname: Xia
mesh_terms: D000493:Allopurinol / Q000494:pharmacology*; D002760:Cholangiopancreatography, Endoscopic Retrograde / Q000009:adverse effects*; D006801:Humans; D015994:Incidence; D010195:Pancreatitis / Q000188:drug therapy* / Q000453:epidemiology / Q000517:prevention & control*; D011446:Prospective Studies; D016032:Randomized Controlled Trials as Topic
chemical_list: D000493:Allopurinol