title: Characteristics of randomized controlled trials on liver transplantation.
abstract: OBJECTIVE
  The randomized controlled trial (RCT) provides the highest quality evidence and plays an important role in establishing evidence-based medicine. Although many RCTs have been performed in the field of liver transplantation (LTx), there has been no analysis of RCTs on LTx. Therefore, this study analyzed the characteristics of RCTs on LTx.
  
  
  METHODS
  A MEDLINE search was performed to identify prospective RCTs on LTx published in the last decade. Eligible RCTs were analyzed using the following items: study theme, publication year, geographical area, sample size, multicenter study, and impact factor.
  
  
  RESULTS
  One hundred and ninety-four papers were eligible for review. Geographically, most RCTs were carried out in Europe and North America. Studies examining the efficacy of immunosuppressants such as tacrolimus and cyclosporine in liver transplant recipients were most frequently performed. RCTs on hepatoprotective agents against liver injury, prophylactic therapy for cytomegalovirus infection, antiviral therapy against hepatitis B or C viral infection, and surgical procedures follow in numerical order. Recently, the number of RCTs on antiviral therapy against hepatitis B or C viral infection is increasing. The average sample number is nearly 100. The rate of multicenter studies among all RCTs is 27%. Interestingly, the rate of multicenter study in the latter half is significantly higher than that in the former half.
  
  
  CONCLUSIONS
  Many RCTs on LTx have been performed all over the world, especially in Europe and North America. RCTs on antiviral therapy against recurrence of hepatitis B or C virus after LTx are increasing in number, since this has recently become a major problem after LTx.
authors.affiliation: Department of Surgery, Otsu Municipal Hospital, 2-9-9 Motomiya, Otsu, Shiga 520-0804, Japan. kaido3@hotmail.com
authors.forename: Toshimi
authors.initials: T
authors.lastname: Kaido
mesh_terms: D006801:Humans; D016031:Liver Transplantation; D016032:Randomized Controlled Trials as Topic