Reliability and validity of the Spanish version of the TAPQOL: a health-related quality of life (HRQOL) instrument for 1- to 5-year-old children.

Objectives: To evaluate the reliability, and construct validity of the Spanish version of the TNO-AZL preschool children quality of life (TAPQOL).

Methods: A consecutive sample of children (3 months to 5 years old) was recruited from primary care centers and two teaching hospitals in Spain. The TAPQOL and a set of questions related to their child's health status were administered to parents. Clinical diagnoses were collected from clinical records. Principal component analysis (PCA) with varimax rotation was used to analyze the instrument's structure. Effect size (ES) and analysis of variance (ANOVA) were used to analyze differences between subgroups known to be in poor health compared to the healthy subgroup.

Results: A total of 228 children participated in the study (response rate=95%). Ten of the 12 scales showed more than 30% ceiling effect. All dimensions except one had Cronbach's alpha coefficients greater than 0.7. PCA explained 75% of the variance. Healthy children in general had better scores than the other subgroups. Children at risk of poor health outcomes and those with respiratory problems scored lower in several scales than the healthy subgroup.

Conclusions: Although the Spanish TAPQOL shows a non-negligible ceiling effect, it seems to be a reliable and valid instrument for Spanish infants and toddlers, and with similar psychometric characteristics to the original version. Future studies should try to improve questionnaire's structure and assess its sensitivity to change.