title: Elevated risk of opportunistic viral infection in patients with Crohn's disease during biological therapies: a meta analysis of randomized controlled trials.
abstract: BACKGROUND
  Biological agents have been widely used in the treatment of Crohn's disease (CD). These drugs carry the risk of excessive immunosuppression, indicating possible opportunistic infections including opportunistic viral infections, but no meta analysis has ever focused on this issue.
  
  
  OBJECTIVE
  To evaluate whether there is an association between biological agents therapy and the risk of opportunistic viral infections and serious infections in patients with CD.
  
  
  METHODS
  A search of online databases was performed and literature selection was carried out according to the inclusion and exclusion criteria by reading titles, abstracts and full texts. Study heterogeneity and publication bias were assessed. Whether to choose a fixed effects model or a random effects model depended on the result of heterogeneity test.
  
  
  RESULTS
  There was a statistical significance in opportunistic viral infection events between the biological agents group and the placebo group. However, our analysis didn't observe statistically significant differences between the two groups when combined analyses were carried out for herpes zoster and herpes simplex separately. A risk trend in the biological agents group was observed in the analysis for herpes zoster. More analyses aimed at the outcome measures and including influenza and serious infection were carried out separately, but no statistical significance was found in them.
  
  
  CONCLUSIONS
  Biological agents use might increase the risk of opportunistic viral infections in patients with CD, but not the risk of herpes simplex and serious infections. More randomized controlled trials (RCTs) are needed to draw the conclusion of whether they could elevate the risk of herpes zoster.
authors.affiliation: Department of Gastroenterology /Hepatology, Zhongnan Hospital of Wuhan University, Donghu Road 169, Wuhan, 430071, People's Republic of China.
authors.forename: Xiaobing
authors.initials: X
authors.lastname: Wang
authors.forename: Feng
authors.initials: F
authors.lastname: Zhou
authors.forename: Junzhang
authors.initials: J
authors.lastname: Zhao
authors.forename: Rui
authors.initials: R
authors.lastname: Zhou
authors.forename: Meifang
authors.initials: M
authors.lastname: Huang
authors.forename: Jin
authors.initials: J
authors.lastname: Li
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Shufang
authors.initials: S
authors.lastname: Xu
authors.forename: Bing
authors.initials: B
authors.lastname: Xia
mesh_terms: D001685:Biological Factors / Q000627:therapeutic use*; D001691:Biological Therapy; D003424:Crohn Disease / Q000188:drug therapy* / Q000453:epidemiology*; D006801:Humans; D009894:Opportunistic Infections / Q000453:epidemiology*; D012306:Risk; D014777:Virus Diseases / Q000453:epidemiology*
chemical_list: D001685:Biological Factors