title: Health-related quality of life advantage of long-acting injectable antipsychotic treatment for schizophrenia: a time trade-off study.
abstract: BACKGROUND
  This study was undertaken to estimate utility values for alternative treatment intervals for long acting antipsychotic intramuscular injections for the treatment of schizophrenia.
  
  
  METHODS
  Vignettes were developed using the published literature and an iterative consultation process with expert clinicians and patient representative groups. Four vignettes were developed. The first was a vignette of relapsed/untreated schizophrenia. The other three vignettes presented a standardised picture of well-managed schizophrenia with variations in the intervals between injections: once every 2-weeks, 4-weeks and 3-months. A standardised time trade off (TTO) approach was used to obtain utility values for the vignettes. As a societal perspective was sought, a representative sample of individuals from across the community (Sydney, Australia) was recruited. Ninety-eight people completed the TTO interview. The vignettes were presented in random order to prevent possible ordering effects.
  
  
  RESULTS
  A clear pattern of increasing utility was observed with increasing time between injections. Untreated schizophrenia was rated as very poor health-related quality of life with a mean (median) utility of 0.27 (0.20). The treated health states were rated at much higher utilities and were statistically significantly different (p < 0.001) from each other: (1) 2-weekly: mean (median) utility = 0.61 (0.65); (2) 4-weekly: mean (median) utility = 0.65 (0.70); (3) 3-monthly: mean (median) utility = 0.70 (0.75).
  
  
  CONCLUSIONS
  This study has provided robust data indicating that approximately a 0.05 utility difference exists between treatment options, with the highest utility assigned to 3-monthly injections.
authors.affiliation: Public Health Innovation, Population Health Strategic Research Centre, Deakin University, 221 Burwood Highway, Burwood, VIC, Australia. richard.osborne@deakin.edu.au
authors.forename: Richard H
authors.initials: RH
authors.lastname: Osborne
authors.forename: Andrew
authors.initials: A
authors.lastname: Dalton
authors.forename: Judy
authors.initials: J
authors.lastname: Hertel
authors.forename: Rudolf
authors.initials: R
authors.lastname: Schrover
authors.forename: Dell Kingsford
authors.initials: DK
authors.lastname: Smith
mesh_terms: D000328:Adult; D000368:Aged; D014150:Antipsychotic Agents / Q000008:administration & dosage* / Q000627:therapeutic use; D001315:Australia; D017281:Cost of Illness; D003692:Delayed-Action Preparations; D004334:Drug Administration Schedule; D004363:Drug Utilization / Q000706:statistics & numerical data / Q000639:trends; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D007273:Injections, Intramuscular / Q000523:psychology / Q000706:statistics & numerical data; D007407:Interviews as Topic; D008297:Male; D008875:Middle Aged; D011788:Quality of Life; D018401:Sample Size; D012559:Schizophrenia / Q000188:drug therapy* / Q000191:economics; D012923:Social Class; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D014150:Antipsychotic Agents; D003692:Delayed-Action Preparations