title: Scientific publications on portal vein thrombosis and Budd-Chiari syndrome: a global survey of the literature.
abstract: OBJECTIVE
  Portal vein thrombosis (PVT) and Budd-Chiari syndrome (BCS) are two rare vascular disorders of the liver that can lead to life-threatening complications. We conducted a global survey to systematically analyze the scientific publications in the fields of PVT and BCS.
  
  
  METHODS
  All papers regarding PVT and BCS were identified via the PubMed, EMBASE, and Cochrane library databases. The publication year, country, type of paper, study design, and number of citations were summarized. Good quality papers were defined as those in which a high proportion of homogeneous patients with BCS and/or PVT was observed.
  
  
  RESULTS
  We identified 6691 and 4325 papers regarding PVT and BCS, respectively. The number of papers gradually increased over time. Researchers from the USA published the greatest number of papers (PVT: n=1418; BCS: n=888). Clinical studies were the most common type of paper (PVT: n=5395; BCS n=3171), but fewer than half of these observed more than 10 patients (PVT: n=2667/5395; BCS: n=1092/3171). Furthermore, fewer than half of the clinical studies with more than 10 patients were of good quality (PVT: 976/2667; BCS: 466/1092). According to the study design, the good quality papers were classified as cohort studies (PVT: n=865; BCS: n=421), case-control studies (PVT: n=98; BCS: n=45), and randomized controlled trials (PVT: n=13; BCS: n=0). The 5 most frequently cited original articles and guidelines/consensuses were also listed.
  
  
  CONCLUSIONS
  Despite an increase in the number of papers regarding PVT and BCS over time, most of the papers had a small sample size, suggesting the necessity of large cohort studies or randomized controlled trials.
authors.affiliation: Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an;Department of Gastroenterology, No. 463 Hospital of Chinese PLA, Shenyang, China. fandaim@fmmu.edu.cn.
authors.forename: Xingshun
authors.initials: X
authors.lastname: Qi
authors.affiliation: Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, China.
authors.forename: Jia
authors.initials: J
authors.lastname: Jia
authors.affiliation: Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, China.
authors.forename: Weirong
authors.initials: W
authors.lastname: Ren
authors.affiliation: Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, China.
authors.forename: Man
authors.initials: M
authors.lastname: Yang
authors.affiliation: Institute of Hematology, Catholic University, Rome, Italy.
authors.forename: Valerio
authors.initials: V
authors.lastname: De Stefano
authors.affiliation: Department of Gastroenterology, No. 463 Hospital of Chinese PLA, Shenyang, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Wang
authors.affiliation: Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, China.
authors.forename: Daiming
authors.initials: D
authors.lastname: Fan
mesh_terms: D015706:Bibliometrics; D035843:Biomedical Research / Q000706:statistics & numerical data; D006502:Budd-Chiari Syndrome / Q000175:diagnosis / Q000209:etiology / Q000628:therapy*; D006801:Humans; D055811:Journal Impact Factor; D011169:Portal Vein; D011643:Publishing / Q000706:statistics & numerical data; D012107:Research Design; D020246:Venous Thrombosis / Q000175:diagnosis / Q000209:etiology / Q000628:therapy*