title: A qualitative examination of the content validity of the EQ-5D-5L in patients with type 2 diabetes.
abstract: BACKGROUND
  The EQ-5D is frequently used to derive utilities for patients with type 2 diabetes (T2D). Despite widely available quantitative psychometric data on the EQ-5D, little is known about content validity in this population. Thus, the purpose of this qualitative study was to examine content validity of the EQ-5D in patients with T2D.
  
  
  METHODS
  Patients with T2D in the UK completed concept elicitation interviews, followed by administration of the EQ-5D-5L and cognitive interviewing focused on the instrument's relevance, clarity, and comprehensiveness.
  
  
  RESULTS
  A total of 25 participants completed interviews (52.0 % male; mean age = 53.5 years). Approximately half (52 %) reported that the EQ-5D-5L was relevant to their experience with T2D. When asked if each individual item was relevant to their experience with T2D, responses varied widely (24.0 % said the self-care item was relevant; 68.0 % said the anxiety/depression item was relevant). Participants frequently said items were not relevant to themselves, but could be relevant to patients with more severe diabetes. Most participants (92.0 %) reported that T2D and/or its treatment/monitoring requirements had an impact on their quality of life that was not captured by the EQ-5D-5L. Common missing concepts included food awareness/restriction (n = 13, 52.0 %); activities (n = 11, 44.0 %); emotional functioning other than depression/anxiety (n = 8, 32.0 %); and social/relationship functioning (n = 8, 32.0 %).
  
  
  CONCLUSIONS
  The results highlight strengths and potential limitations of the EQ-5D-5L, including missing content that could be important for some patients with T2D. Suggestions for addressing limitations are provided.
authors.affiliation: Outcomes Research, Evidera, 7101 Wisconsin Avenue, Suite 1400, Bethesda, MD, 20814, USA. louis.matza@evidera.com.
authors.forename: Louis S
authors.initials: LS
authors.lastname: Matza
authors.affiliation: Global Patient Outcomes and Real World Evidence, Eli Lilly & Co., Indianapolis, IN, USA. boye_kristina_secnik@lilly.com.
authors.forename: Kristina S
authors.initials: KS
authors.lastname: Boye
authors.affiliation: Outcomes Research, Evidera, 7101 Wisconsin Avenue, Suite 1400, Bethesda, MD, 20814, USA. Katie.stewart@evidera.com.
authors.forename: Katie D
authors.initials: KD
authors.lastname: Stewart
authors.affiliation: Global Medical Affairs, Eli Lilly & Co., Indianapolis, IN, USA. curtis_bradley_h@lilly.com.
authors.forename: Bradley H
authors.initials: BH
authors.lastname: Curtis
authors.affiliation: ERT, Peterborough, UK. matthew.reaney@ert.com.
authors.forename: Matthew
authors.initials: M
authors.lastname: Reaney
authors.affiliation: Outcomes Research, Evidera, 7101 Wisconsin Avenue, Suite 1400, Bethesda, MD, 20814, USA. Amanda.landrian@evidera.com.
authors.forename: Amanda S
authors.initials: AS
authors.lastname: Landrian
mesh_terms: D000328:Adult; D003924:Diabetes Mellitus, Type 2 / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011594:Psychometrics / Q000295:instrumentation*; D036301:Qualitative Research; D011788:Quality of Life / Q000523:psychology*; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires; D006113:United Kingdom