The development of a SpA-specific health utility index based on the ASAS Health Index and representing the societal perspective
Background: Choosing between diagnostic or treatment options is typical for healthcare. The aim of these choices is to maximise health. Classic instruments to measure health, such as the SF-36 or ASAS-HI, represent the “impact” of disease on persons but not necessarily the “preferences” of persons for one health state over the other. Health utilities are developed to understand the “preferences” for health states, and are used to support decisions. Traditionally, healthcare payers rely on health utilities when deciding on allocation of societal resources on an innovative option that claim to improve health. Payers traditionally rely on the societal perspective of health preferences and consider them in the context of health-economic evaluations. Depending on the purpose of decision making, disease specific or generic health utilities are used. As preferences for health are culturally influenced, healthcare authorities use country-specific utility values.
Aim: To develop a health utility valuation for SpA based on the new ASAS-Health Index.
Methodology: Using the 17 items of the ASAS Health Index (HI), a best-worst scaling choice task quantified the relative importance score of each of 17 items. To rescale the relative importance-scores of all items on the absolute utility-scale between zero (corresponding to death) and 1 (perfect health), a Time Trade off experiment was conducted, one for ‘severe SpA’ and one for ‘best’ health.
Results: In total, 3,039 subjects (at least 500/country), mean age 46.5 years (SD15.2) and 52.2% women completed the experiments. Six country specific and on general algorithm were derived. The algorithm performed well in patients with axial SpA, independent of the subtype and with a good discriminative ability between patients with low and high disease activity.
Conclusions: Six country-specific and one general algorithm are available to convert scores from the ASAS HI into a disease specific societal utility-value.
Timelines of the project: 2015 – 2019
PI: Annelies Boonen, Maastricht, the Netherlands
Steering committee: Uta Kiltz, Herne, Germany; Jurgen Braun, Herne, Germany; Desiree van der Heijde, Leiden, the Netherlands
Working group: Mickael Hiligsmann, Maastricht, the Netherlands, and Nick Bansback, Vancouver, the Netherlands
Essers I, Hiligsmann M, Kiltz U, Bansback N, Braun J, van der Heijde D, Boonen A. Development of one general and six country-specific algorithms to assess societal health utilities based on ASAS HI. RMD Open. 2019 May 21;5(1):e000872.