title: Tinnitus handicap inventory for evaluating treatment effects: which changes are clinically relevant?
abstract: OBJECTIVE
  To determine the minimum change of the Tinnitus Handicap Inventory (THI) score that could be considered clinically relevant, the authors compared the absolute change of the THI with the Clinical Global Impression–Improvement (CGI-I) score.
  
  
  METHODS
  International studies register with standardized data collection.
  
  
  METHODS
  Tinnitus Research Initiative (TRI).
  
  
  METHODS
  Two hundred ten patients of the TRI database were eligible for this study. In the first analysis, the THI score change and CGI-I ratings were compared with equipercentile linking. In a second analysis, the authors categorized the CGI-I into the 4 groups much better or better, minimally better, no change, and worse and calculated the corresponding differences of the THI score and the effect sizes. An effect size separating the minimally better and the no-change groups was chosen, and the referring THI mean score difference was calculated.
  
  
  RESULTS
  According to the linking method, a CGI-I value of 3 (minimally better) corresponded to a THI score reduction of 6 to 16, whereas the CGI-I value of 4 (no change) corresponded to the range between improvement by 5 points and worsening by 4 points. For separating the no-change and minimally better groups, an effect size d = 0.5 was determined, resulting in a minimal clinically relevant difference of ΔTHI = 7.
  
  
  CONCLUSIONS
  Two different methods yielded comparable results in identifying a reduction in the THI score of 6 and 7 points, respectively, as the minimal clinically relevant change. This study provides a first orientation for sample size calculations and for planning the design of future studies.
authors.affiliation: Center for Clinical Studies, University Hospital Regensburg, Germany. florian.zeman@klinik.uni-regensburg.de
authors.forename: Florian
authors.initials: F
authors.lastname: Zeman
authors.forename: Michael
authors.initials: M
authors.lastname: Koller
authors.forename: Ricardo
authors.initials: R
authors.lastname: Figueiredo
authors.forename: Andreia
authors.initials: A
authors.lastname: Aazevedo
authors.forename: Marcello
authors.initials: M
authors.lastname: Rates
authors.forename: Claudia
authors.initials: C
authors.lastname: Coelho
authors.forename: Tobias
authors.initials: T
authors.lastname: Kleinjung
authors.forename: Dirk
authors.initials: D
authors.lastname: de Ridder
authors.forename: Berthold
authors.initials: B
authors.lastname: Langguth
authors.forename: Michael
authors.initials: M
authors.lastname: Landgrebe
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003939:Diagnostic Techniques, Otological; D004185:Disability Evaluation; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010036:Otolaryngology / Q000379:methods*; D011446:Prospective Studies; D011788:Quality of Life; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D014012:Tinnitus / Q000175:diagnosis / Q000534:rehabilitation*; D016896:Treatment Outcome; D055815:Young Adult