title: Evaluation of item candidates for a diabetic retinopathy quality of life item bank.
abstract: OBJECTIVE
  We are developing an item bank assessing the impact of diabetic retinopathy (DR) on quality of life (QoL) using a rigorous multi-staged process combining qualitative and quantitative methods. We describe here the first two qualitative phases: content development and item evaluation.
  
  
  METHODS
  After a comprehensive literature review, items were generated from four sources: (1) 34 previously validated patient-reported outcome measures; (2) five published qualitative articles; (3) eight focus groups and 18 semi-structured interviews with 57 DR patients; and (4) seven semi-structured interviews with diabetes or ophthalmic experts. Items were then evaluated during 3 stages, namely binning (grouping) and winnowing (reduction) based on key criteria and panel consensus; development of item stems and response options; and pre-testing of items via cognitive interviews with patients.
  
  
  RESULTS
  The content development phase yielded 1,165 unique items across 7 QoL domains. After 3 sessions of binning and winnowing, items were reduced to a minimally representative set (n = 312) across 9 domains of QoL: visual symptoms; ocular surface symptoms; activity limitation; mobility; emotional; health concerns; social; convenience; and economic. After 8 cognitive interviews, 42 items were amended resulting in a final set of 314 items.
  
  
  CONCLUSIONS
  We have employed a systematic approach to develop items for a DR-specific QoL item bank. The psychometric properties of the nine QoL subscales will be assessed using Rasch analysis. The resulting validated item bank will allow clinicians and researchers to better understand the QoL impact of DR and DR therapies from the patient's perspective.
authors.affiliation: Department of Ophthalmology, Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, University of Melbourne, 32 Gisborne St, East Melbourne, VIC, 3002, Australia.
authors.forename: Eva K
authors.initials: EK
authors.lastname: Fenwick
authors.forename: Konrad
authors.initials: K
authors.lastname: Pesudovs
authors.forename: Jyoti
authors.initials: J
authors.lastname: Khadka
authors.forename: Gwyn
authors.initials: G
authors.lastname: Rees
authors.forename: Tien Y
authors.initials: TY
authors.lastname: Wong
authors.forename: Ecosse L
authors.initials: EL
authors.lastname: Lamoureux
mesh_terms: D003930:Diabetic Retinopathy / Q000523:psychology*; D004644:Emotions; D017144:Focus Groups; D006801:Humans; D007407:Interviews as Topic; D017063:Outcome Assessment, Health Care / Q000379:methods*; D011594:Psychometrics / Q000379:methods; D036301:Qualitative Research; D011788:Quality of Life; D011795:Surveys and Questionnaires