Validation of a computer-adaptive test to evaluate generic health-related quality of life
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RESEARCH
Open Access
Validation of a computer-adaptive test to evaluate generic health-related quality of life Pablo Rebollo1*, Ignacio Castejón1, Jesús Cuervo1, Guillermo Villa1, Eduardo García-Cueto2, Helena Díaz-Cuervo1, Pilar C Zardaín1, José Muñiz2, Jordi Alonso3,4, the Spanish CAT-Health Research Group
Abstract Background: Health Related Quality of Life (HRQoL) is a relevant variable in the evaluation of health outcomes. Questionnaires based on Classical Test Theory typically require a large number of items to evaluate HRQoL. Computer Adaptive Testing (CAT) can be used to reduce tests length while maintaining and, in some cases, improving accuracy. This study aimed at validating a CAT based on Item Response Theory (IRT) for evaluation of generic HRQoL: the CAT-Health instrument. Methods: Cross-sectional study of subjects aged over 18 attending Primary Care Centres for any reason. CATHealth was administered along with the SF-12 Health Survey. Age, gender and a checklist of chronic conditions were also collected. CAT-Health was evaluated considering: 1) feasibility: completion time and test length; 2) content range coverage, Item Exposure Rate (IER) and test precision; and 3) construct validity: differences in the CAT-Health scores according to clinical variables and correlations between both questionnaires. Results: 396 subjects answered CAT-Health and SF-12, 67.2% females, mean age (SD) 48.6 (17.7) years. 36.9% did not report any chronic condition. Median completion time for CAT-Health was 81 seconds (IQ range = 59-118) and it increased with age (p < 0.001). The median number of items administered was 8 (IQ range = 6-10). Neither ceiling nor floor effects were found for the score. None of the items in the pool had an IER of 100% and it was over 5% for 27.1% of the items. Test Information Function (TIF) peaked between levels -1 and 0 of HRQoL. Statistically significant differences were observed in the CAT-Health scores according to the number and type of conditions. Conclusions: Although domain-specific CATs exist for various areas of HRQoL, CAT-Health is one of the first IRTbased CATs designed to evaluate generic HRQoL and it has proven feasible, valid and efficient, when administered to a broad sample of individuals attending primary care settings.
Background Health-Related Quality of Life (HRQoL) is among the most used variables in Health Outcomes Research (HOR) in the academic field, as well as in clinical trials and post-authorisation studies. It refers to the subjective valuation of the influence of health on the individuals’ ability of having a normal functioning which makes it possible to perform all the activities which are important for them and which affect their well-being [1]. Although during the last 35 years HRQoL assessment has had an enormous development worldwide, several barriers limit * Correspondence: [email protected] 1 BAP Health Outcomes Research, Calle Azcárraga 12 A, 33010, Oviedo, Spain Full list of author information is available at the end of the article
its use in the clini
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