Reliability and validity of a novel haemophilia-specific self-efficacy scale

Higher self-efficacy in chronic disease patients is associated with higher development of self-management skills and increased quality-of-life. Quantification and monitoring of self-efficacy is therefore of importance. Self-efficacy in haemophilia patients has received little attention due to lack of standardized scales. To validate the novel Haemophilia-specific Self-Efficacy Scale (HSES) in haemophilia patients on prophylactic home treatment, haemophilia patients aged 1-18 years on prophylactic treatment ≥1 year were included from three Dutch Haemophilia Treatment Centres. The HSES consists of 12 items, relating to perceptions of the ability to function on a day-to-day basis with regard to patient's disease. Retest was performed in a subsample. Validity was proven by the General Self-Efficacy Scale and by the health-related quality-of-life assessment tool Haemo-QoL. Data were analysed from 53 children (response 75%), with a mean age of 9.8 years (SD 4.0). Mean total scale score of HSES was 55.5 (SD 4.7; range 38-60), with a ceiling effect of 17%. The HSES showed adequate internal consistency (Cronbach's alpha 0.72) and good test-retest reliability (Intra-Class-Correlation coefficient 0.75; P < 0.01; n = 37). The convergent validity was adequate as haemophilia-specific self-efficacy correlated significantly with general self-efficacy (r = 0.38; P < 0.01). High HSES scores correlated significantly with quality-of-life as measured by the Haemo-QoL (r = -0.42; P ≤ 0.01). The novel HSES is a reliable and valid tool to assess self-efficacy in paediatric haemophilia patients on prophylactic home treatment. High self-efficacy correlated with higher quality-of-life, further underlining the importance to standardly assess, monitor and improve self-efficacy.