Development and validation of a measure of disease-specific quality of life in young children with haemophilia.

Summary. No disease-specific tool for measuring health-related quality of life (HRQL), an important outcome when assessing medical treatment, has been developed for children with haemophilia. The goal of this study was to develop a parent-administered questionnaire for evaluating quality of life (QOL) in paediatric haemophilia patients between 2 and 6 years of age. After interviewing physicians (5), nurses (5) and parents (10) of children with haemophilia aged between 2 and 6 years, 92 questions were developed and pilot-tested with parents (44) of children with haemophilia to create a 39-question instrument that assessed somatic symptoms, physical functioning, sleep disturbance, stigma, social functioning, fear/resentment, mood/behaviour, restrictions, treatment upset, haemophilia concern and energy level. Reliability and validity were evaluated with 103 parents of children with haemophilia and parents of 249 age- and gender-matched healthy children. Estimates of scale reliability (internal consistency) for eight multi-item scales ranged from 0.73 to 0.94. Results showed construct validity (correlations with age, severity of haemophilia, treatment type, days absent and days confined to bed) and correlated with two general, paediatric quality-of-life instruments (Impact on Family Scale and Functional Status II(R). Discriminant validity was demonstrated by comparing scores between patients receiving/not receiving prophylactic therapy and between haemophilia patients and healthy controls. This disease-specific HRQL measure should be of use in clinical trials and general practice to better understand disease and treatment impacts in young children with haemophilia.