title: The responsiveness of quality of life utilities to change in depression: a comparison of instruments (SF-6D, EQ-5D, and DFD).
abstract: BACKGROUND
  Utilities are often a main outcome parameter in economic evaluations. Because depression has a large influence on quality of life, it is expected that utilities are responsive to changes in depression.
  
  
  OBJECTIVE
  To evaluate the change in utility derived from different instruments in depression, including the Short Form 6D (SF-6D), the Euroqol based on the UK (EQ-5D(UK)), the Euroqol based on the Dutch tariff (EQ-5D(NL)), and utilities derived from Beck Depression Inventory Second Edition (BDI-II) using the Depression-Free-Day method.
  
  
  METHODS
  This study evaluated the responsiveness, the minimally important difference, and the agreement in utility change derived from the different instruments.
  
  
  RESULTS
  The SF-6D, EQ-5D(UK), and EQ-5D(NL) were responsive. The minimally important difference values are in line with previous studies, about 0.3. The Depression-Free-Day method nearly always resulted in positive utility changes, even for subgroups that had no change or deterioration in health status or depression. There was poor agreement between utility changes of the SF-6D, EQ-5D (either EQ-5D(UK) or EQ-5D(NL)), and DFDu.
  
  
  CONCLUSIONS
  The SF-6D, EQ-5D(UK), and EQ-5D(NL) seem responsive and thus adequate for estimating utility in depression treatment. We do not recommend the use of the Depression-Fee-Day method. The low agreement between utility changes indicates that outcomes of the different instruments are incomparable.
authors.affiliation: Department of Clinical Psychological Science, Faculty of Psychology, Maastricht University, The Netherlands. S.Gerhards@maastrichtuniversity.nl
authors.forename: Sylvia A H
authors.initials: SA
authors.lastname: Gerhards
authors.forename: Marcus J H
authors.initials: MJ
authors.lastname: Huibers
authors.forename: Kevin A T M
authors.initials: KA
authors.lastname: Theunissen
authors.forename: L Esther
authors.initials: LE
authors.lastname: de Graaf
authors.forename: Guy A M
authors.initials: GA
authors.lastname: Widdershoven
authors.forename: Silvia M A A
authors.initials: SM
authors.lastname: Evers
mesh_terms: D000328:Adult; D003863:Depression / Q000175:diagnosis* / Q000523:psychology / Q000628:therapy; D005260:Female; D006304:Health Status; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D011237:Predictive Value of Tests; D011788:Quality of Life; D016032:Randomized Controlled Trials as Topic; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D013997:Time Factors; D016896:Treatment Outcome