A Systematic Review of the Feasibility and Psychometric Properties of the ICECAP-A Capability Instrument and Its Use So Far in Economic Evaluation

Objectives: Development of the ICECAP-A capability instrument was reported in 2012; use of certain capability measures was suggested in the context of social/long-term care soon afterwards by decision-making organisations in the UK and Netherlands. Despite enthusiasm for ICECAP-A this study represents the first attempt to collate evidence on its psychometric properties, and its use in economic analysis.
Methods: A systematic review of studies published between January 2012 and February 2019 which have either explored the psychometric properties of ICECAP-A (validity, reliability and responsiveness), or report its use in economic analysis.
Results: 27 studies were identified, 11 undertaking some form of economic analysis (including pilot and feasibility studies) and 16 assessing psychometric properties (seven assessing construct validity). ICECAP-A has mainly been used in the UK, but also in other English speaking countries and in Europe, across a wide range of healthcare contexts. There is promising evidence on content validity, construct validity and responsiveness. Whilst there was consistently strong association between ICECAP-A and AQoL-8D, associations with EQ-5D-3L and 5L were inconsistent. In some cases it was found that a switch in evaluative space from health to capability wellbeing would alter resource allocation decisions.
Discussion: ICECAP-A is correlated with health related quality of life (HRQoL), but is most appropriately regarded as a complement for and not a substitute to EQ-5D in particular. Positive evidence of the measure’s content and construct validity is beginning to accumulate, but further conceptual and policy debate is needed regarding the equity implications of switching between evaluative spaces.