Validation of QUALAS-T, a health-related quality of life instrument for teenagers with spina bifida

Abstract

Introduction We aimed to develop and validate a self-reported QUAlity of Life Assessment in Spina bifida for Teenagers (QUALAS-T). Material and methods We drafted a 46-question pilot instrument using a patient-centered comprehensive item generation/refinement process. A group of 13–17 years olds with spina bifida (SB) was recruited online via social media and in person at SB clinics (2013–2015). Healthy controls were recruited during routine pediatrician visits. Final questions were identified based on clinical relevance, factor analysis and domain psychometrics. Teenagers with SB completed the validated generic Kidscreen-27 instrument. Results Median age of 159 participants was 15.2 years (42.0% male, 77.4% Caucasian), similar to 58 controls (p ≥ 0.06). There were 102 online and 57 clinic participants (82.8% of eligible). Patients, parents and an expert panel established face and content validity of the 2-domain, 10-question QUALAS-T. Internal consistency and test-retest reliability were high for the Family and Independence and Bladder and Bowel domains (Cronbach's alpha: 0.76–0.78, ICC: 0.72–0.75). The Bladder and Bowel domain is the same for QUALAS-T , QUALAS-A for adults and QUALAS-C for children. Correlations between QUALAS-T domains were low (r = 0.34), indicating QUALAS-T can differentiate between distinct HRQOL components. Correlations between QUALAS-T and Kidscreen-27 were also low (r ≤0.41). QUALAS-T scores were lower in teenagers with SB than without (p <0.0001). Conclusions QUALAS-T is a short, valid HRQOL tool for adolescents with SB, applicable in clinical and research settings. Since the Bladder & Bowel domains for all QUALAS versions are the same, Bladder and Bowel HRQOL can be measured on the same scale from age 8 through adulthood.