Reliability and validity of the VSP-A, a health-related quality of life instrument for ill and healthy adolescents

Abstract

Purpose: To report the preliminary validation results of a generic self-administered measure for adolescents the VSP-A (Vecu et Sante Percue de l'Adolescent).

Methods: The validation survey of the 37-item VSP-A involved 1938 adolescents: 1758 adolescents attending school (90.7%) and 180 inpatient youths (9.3%) with medical, surgical, or psychiatric conditions; mean age was 14.8 years (SD = 2.1; range = 10-17) and 1018 (52.5%) were girls. Ten dimensions scores were computed: psychological well-being, body image, physical well-being, vitality, friends, parents, teachers, school performance, medical staff, and a global HRQL index. Construct validity was tested using inter-item correlations, item-dimension correlations, and principal component analysis. The unidimensionality of the scales was studied using Rasch rating scale model and the internal consistency of the scales using Cronbach alpha. Known group comparisons were performed and effect sizes computed to assess the clinical validity and sensitivity of the instrument.

Results: VSP-A, completed in less than 15 minutes, is consistent (Cronbach alpha = 0.74-0.91). Content and construct validity are good. Factorial validity, item-internal consistency, item-discriminant validity, and inter-dimension correlations support the item grouping in 10 dimensions. The results of the comparison of the VSP-A scores according to external criteria (sociodemographics, health status) show they are in accordance with the literature and previous works.

Conclusions: These preliminary results support the reliability and validity of the VSP-A as a multidimensional adolescent report of HRQL in healthy and patient populations. The next phase of the research consists of testing the sensitivity to changes of the VSP-A.