title: Overall similarity and consistency assessment scores are not sufficiently accurate for predicting discrepancy between direct and indirect comparison estimates.
abstract: OBJECTIVE
  Indirect comparison methods have been increasingly used to assess the effectiveness of different interventions comparatively. This study evaluated a Trial Similarity and Evidence Consistency Assessment (TSECA) framework for assessing key assumptions underlying the validity of indirect comparisons.
  
  
  METHODS
  We applied the TSECA framework to 94 Cochrane Systematic Reviews that provided data to compare two interventions by both direct and indirect comparisons. Using the TSECA framework, two reviewers independently assessed and scored trial similarity and evidence consistency. A detailed case study provided further insight into the usefulness and limitations of the framework proposed.
  
  
  RESULTS
  Trial similarity and evidence consistency scores obtained using the assessment framework were not associated with statistically significant inconsistency between direct and indirect estimates. The case study illustrated that the assessment framework could be used to identify potentially important differences in participants, interventions, and outcome measures between different sets of trials in the indirect comparison.
  
  
  CONCLUSIONS
  Although the overall trial similarity and evidence consistency scores are unlikely to be sufficiently accurate for predicting inconsistency between direct and indirect estimates, the assessment framework proposed in this study can be a useful tool for identifying between-trial differences that may threaten the validity of indirect treatment comparisons.
authors.affiliation: Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich, Norfolk, NR4 7TJ, UK.
authors.forename: Tengbin
authors.initials: T
authors.lastname: Xiong
authors.forename: Sheetal
authors.initials: S
authors.lastname: Parekh-Bhurke
authors.forename: Yoon K
authors.initials: YK
authors.lastname: Loke
authors.forename: Asmaa
authors.initials: A
authors.lastname: Abdelhamid
authors.forename: Alex J
authors.initials: AJ
authors.lastname: Sutton
authors.forename: Alison J
authors.initials: AJ
authors.lastname: Eastwood
authors.forename: Richard
authors.initials: R
authors.lastname: Holland
authors.forename: Yen-Fu
authors.initials: YF
authors.lastname: Chen
authors.forename: Tanya
authors.initials: T
authors.lastname: Walsh
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Glenny
authors.forename: Fujian
authors.initials: F
authors.lastname: Song
mesh_terms: D015982:Bias; D019317:Evidence-Based Medicine / Q000592:standards*; D019983:Guideline Adherence / Q000592:standards*; D006801:Humans; D017410:Practice Guidelines as Topic / Q000592:standards*; D011237:Predictive Value of Tests; D011785:Quality Assurance, Health Care; D016032:Randomized Controlled Trials as Topic / Q000592:standards*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity