E-QALY: psychometric testing and selecting the items for a new generic preference-based measure

PEASGOOD, TESSA; MUKURIA, CLARA; BRAZIER, JOHN; MARTEN, OLE; KREIMEIER, SIMONE; LUO, NAN; MULHERN, BRENDAN; GREINER, WOLFGANG; PICKARD, A. SIMON; AUGUSTOVSKI, FEDERICO; ENGEL, LIDIA; GIBBONS, LUZ; YANG, ZHIHAO; MONTEIRO, ANDREA L.; KUHARIC, MAJA; BELIZÁN, MARÍA; BJØRNER, JAKOB

Quality of life research : an international journal of quality of life aspects of treatment, care and rehabilitation

NLM (Medline)

Año: 2020 vol. 29 p. 1 - 196

Aims: The aim was to quantitatively test the items from a psychometricperspective to further inform the selection of items for both aprofile measure and a health state classification system for valuation.Methods: Self-administered paper and online surveys were conductedin six countries (Argentina, Australia, China, United Kingdom, Germanyand the USA) with individuals with various physical and mentalhealth conditions, carers and social care users to test the psychometricproperties of the proposed domains and 66 draft items using a standardizedprotocol. Analysis included examination of responsedistribution, sensitivity to known group differences, testing ofdimensionality by means of exploring item correlations, exploratoryand confirmatory factor analysis as well as exploration of itemresponse theory models. A consultation exercise was used to selectitems for the final measure. Results: Survey data from * 4500 participantsacross all countries were available. German results (n = 496)suggest that 4 items performed poorly while 11 items performed wellover all psychometric analyses. Evidence on the remaining items wasless conclusive with no clear pattern of superior or inferior psycho-metric item performance over items in the same (sub-)domain asE-QALY: psychometric testing and selecting the items for a newgeneric preference-based measureitems’ strengths and weaknesses across analyses methods varied.Internationally, a few items on self-care (‘activity’) seemed problematicfor all language versions. There was variation in performanceacross country results for items on control (‘autonomy’) and items onhappiness, hope and safety (‘feelings’). Items on the physical domainlike pain, or sleep, concentration (‘cognition’) and meaningfulactivities (‘activity’) indicated a consistently good performance.Dimensionality was the same across most of the countries with theexception of China where anxiety, safety, anger, happiness, hope,coping, self-worth were combined. Consultation resulted in the final25-item measure and 9-item classification system. Conclusion: Evidencefrom different countries provided in-depth knowledge on crossculturalitem performance although synthesizing the findings waschallenging. The overall psychometric performance of individualitems was very similar but the individual country data allowed itemprioritization which was used to inform the final measure.