title: Assessment of self-injection experience in patients with rheumatoid arthritis: psychometric validation of the Self-Injection Assessment Questionnaire (SIAQ).
abstract: BACKGROUND
  Subcutaneous self-injection of medication has benefits for the patient and healthcare system, but there are barriers such as dexterity problems and injection anxiety that can prevent self-injection being used effectively. An accurate method of evaluating patients' experiences with self-injection would enable assessment of their success in giving self-injections and the likelihood of them adhering to a self-injection regimen. The aim of this study was to develop a questionnaire to measure overall patient experience with subcutaneous self-injection (the Self-Injection Assessment Questionnaire [SIAQ]), and to investigate its psychometric properties.
  
  
  METHODS
  The construct validity and reliability of the SIAQ were tested in patients with rheumatoid arthritis who volunteered to inject certolizumab pegol using a standard syringe during an open-label multinational extension trial of the long-term safety and efficacy of this drug. The SIAQ PRE module was self-completed before the first self-injection, and the POST module was self-completed following each of three fortnightly self-injections.
  
  
  RESULTS
  Ninety-seven patients completed the SIAQ. All items correlated well with their respective domains in confirmatory factor analysis. As predicted, compared with other participants, patients with very low scores (less than 3 out of 10) in PRE causal domains (Feelings about injections and Self-confidence) were significantly less satisfied with their first self-injection, as were patients with a very low score in any POST causal domain (Self-confidence, Feelings about injections, Injection-site reactions and Ease of use), demonstrating known-groups validity. Causal domain scores generally correlated most strongly with the Satisfaction with self-injection domain, supporting convergent validity. The SIAQ demonstrated internal consistency and reproducibility; Cronbach's α and the test-retest coefficient were > 0.70 for all domains. Sensitivity and responsiveness were also shown, where measurable. Each language version showed structural validity.
  
  
  CONCLUSIONS
  The SIAQ was demonstrated to be a valid, reliable tool in patients with rheumatoid arthritis.
authors.affiliation: UCB Pharma SA, Brussels, Belgium. Geoffroy.Coteur@ucb.com.
authors.forename: Dorothy
authors.initials: D
authors.lastname: Keininger
authors.forename: Geoffroy
authors.initials: G
authors.lastname: Coteur
mesh_terms: D000328:Adult; D000368:Aged; D018501:Antirheumatic Agents / Q000008:administration & dosage; D001172:Arthritis, Rheumatoid / Q000188:drug therapy* / Q000523:psychology; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D007279:Injections, Subcutaneous; D008297:Male; D008875:Middle Aged; D011594:Psychometrics / Q000592:standards*; D011788:Quality of Life; D015203:Reproducibility of Results; D012646:Self Administration / Q000523:psychology*; D011795:Surveys and Questionnaires
chemical_list: D018501:Antirheumatic Agents