ICECAP-O, the current state of play: a systematic review of studies reporting the psychometric properties and use of the instrument over the decade since its publication

Abstract

PurposeA paper reporting the development of the ICECAP-O was published in 2006. Since then, there has been increasing interest in the use of capability-based measures within health economics and the ICECAP-O has been suggested for use in economic evaluation by decision-making bodies in the Netherlands and UK.MethodsA systematic review of studies published between January 2006 and October 2018 which have assessed the psychometric properties of ICECAP-O or utilised the measure within economic evaluation.ResultsTwenty-four studies explored the psychometric properties of ICECAP-O and 21 have utilised the measure within economic evaluation; one study reported psychometric properties as well as utilising the measure within economic evaluation. The ICECAP-O has good construct validity and responsiveness, but there is evidence of some issues relating to content validity. In the context of economic evaluation, the ICECAP-O has, to date, mainly been included as a secondary economic measure and the reporting of results is brief with minimal detail and often no discussion. Five of the economic evaluation studies combined scores from ICECAP-O with time, but each used different terminology to describe this result.ConclusionFocus, in terms of publications, appears to have shifted now from assessment of psychometric properties to the utilisation of the ICECAP-O within economic evaluation. Further research is needed with respect to a decision-rule for the ICECAP measures. This additional research should also guide users in terms of appropriate analysis, terminology and presentation of results, which are in-keeping with the conceptual framework underpinning the ICECAP-O.