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

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.