Validation of the Haemophilia & Exercise Project-Test-Questionnaire (HEP-Test-Q)-An instrument for the assessment of subjective physical functioning in children with haemophilia.

Abstract

Contemporary haemophilia management recommends sport and physical activity in children with haemophilia. Assessment of subjective physical functioning requires standardized and validated instruments. To adapt and psychometrically test the adult Haemophilia & Exercise Project-Test-Questionnaire (HEP-Test-Q) for children (aged 6-17years). In discussion rounds with children, single items of the adult HEP-Test-Q were reformulated to make them understandable without changing the item concept. The validation of the child-adapted version in children with haemophilia (n=228) included pre-testing with feasibility testing, cognitive interviewing (n=34), pilot-testing of the revised version in the EIS Study (n=67) and field-testing in the SO-FIT Study (n=127). Pre-testing revealed a completion time of 8.2±4.1minutes and children liked the instrument. Cognitive interviews demonstrated that most items were easy to understand; 9 items were reformulated. Pilot-testing demonstrated good psychometric characteristics in terms of reliability (α=.94 Total Score) and validity. Convergent validity testing showed moderate correlations with the Haemo-QoL (r=-.491), but low correlations with the Petrini Score (r=-.293). Known groups' validity revealed significant differences in clinical subgroups; chronic pain (P<.002) and target joints (P<.021). Field-testing confirmed psychometric characteristics; Cronbach's alpha ranged from α=.80 ("endurance") to α=.94 (Total Score). The child-adapted HEP-Test-Q showed moderate correlations with the PedHAL (r=.634, P<.0001) and the Haemo-QoL SF (r=-.575, P<.0001). Known groups' validity testing proved that the HEP-Test-Q could discriminate between clinical subgroups. The child-adapted HEP-Test-Q is a short, practical and acceptable instrument for the assessment of subjective physical functioning. Outcomes can be compared to adults because item concepts are identical to the adult version.