title: National EQ-5D tariffs and quality-adjusted life-year estimation: comparison of UK, US and Danish utilities in south Swedish rheumatoid arthritis patients.
abstract: OBJECTIVE
  To study how the choice of national EQ-5D tariff may affect utility and incremental quality-adjusted life-year (QALY) estimates.
  
  
  METHODS
  South Swedish rheumatoid arthritis patients in an observational study, starting and continuing anti-tumour necrosis factor (TNF) monotherapy (n=54) or anti-TNF plus methotrexate (n=215) for 1 year during May 2002 to April 2009, were included. EQ-5D questionnaires were completed at baseline, 3, 6 and 12 months. Utilities and accumulated QALY were compared using the UK, US and Danish EQ-5D tariffs. Utilities for all 243 possible EQ-5D health states were also compared.
  
  
  RESULTS
  US utilities were generally higher than UK, with Danish falling in between. A substantial 1-year mean utility improvement was seen in both study groups using all tariffs (UK 0.28 vs 0.29; US 0.18 vs 0.19; Danish 0.20 vs 0.22). Adjusting for baseline differences between groups, the incremental QALY gain of combined treatment was 0.09 using the UK tariff, while 0.06 according to both US and Danish tariffs. Inter-tariff disagreement in utility and accumulated QALY varied irregularly across the range of utilities.
  
  
  CONCLUSIONS
  Applying different national EQ-5D tariffs to the same data may result in substantially different incremental QALY estimates, crucial knowledge when interpreting cost-utility analyses. Studies using different tariffs cannot be directly compared.
authors.affiliation: Department of Clinical Sciences Lund, Section of Rheumatology, Lund University, Sweden. johan.81.karlsson@gmail.com
authors.forename: Johan A
authors.initials: JA
authors.lastname: Karlsson
authors.forename: Jan-Åke
authors.initials: JÅ
authors.lastname: Nilsson
authors.forename: Martin
authors.initials: M
authors.lastname: Neovius
authors.forename: Lars-Erik
authors.initials: LE
authors.lastname: Kristensen
authors.forename: Anders
authors.initials: A
authors.lastname: Gülfe
authors.forename: Tore
authors.initials: T
authors.lastname: Saxne
authors.forename: Pierre
authors.initials: P
authors.lastname: Geborek
mesh_terms: D018501:Antirheumatic Agents / Q000627:therapeutic use; D001172:Arthritis, Rheumatoid / Q000188:drug therapy / Q000534:rehabilitation*; D003431:Cross-Cultural Comparison; D003718:Denmark; D004359:Drug Therapy, Combination; D006305:Health Status Indicators; D006801:Humans; D008727:Methotrexate / Q000627:therapeutic use; D011594:Psychometrics; D019057:Quality-Adjusted Life Years; D013548:Sweden; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors; D006113:United Kingdom; D014481:United States
chemical_list: D018501:Antirheumatic Agents; D014409:Tumor Necrosis Factor-alpha; D008727:Methotrexate