Longitudinal validation of the Caregiver Priorities and Child Health Index of Life with Disabilities in a Dutch sample of nonambulatory children with severe disabilities.

[BACKGROUND] The purpose of this study was to evaluate the longitudinal validity of the Dutch version of the Caregiver Priorities and Child Health Index of Life with Disabilities (CPCHILD), a health-related quality of life instrument for nonambulatory children with severe motor disabilities and accompanying disorders.

[METHODS] The effect of two interventions, Botox injections in the hip region and percutaneous endoscopic gastrostomy, was followed over time. Caregivers (n = 38) of nonambulatory children (26 boys, 12 girls; mean age: 9 years, 5 months [4 years, 9 months]) with severe disabilities completed the questionnaire prior to the intervention, at 3 months and 6 months follow up. Seven a priori hypotheses were formulated. Longitudinal validity was analysed by a paired t test of the pre-post scores and correlation analysis between the change-scores and two external criteria: a caregivers' perceived change in health-related quality of life of the child questionnaire and a general health-related quality of life instrument.

[RESULTS] The results reported here follow completely the pattern we hypothesized for four analyses and partially in the remaining three. In the Botox group, the mean change-score at 3 months was 6.9 points (p < 0.05), which exceeds the minimal clinically important difference of 5.8 points. At 6 months, the effect was diminished to 4.5 points, in line with the temporary effect of Botox. There were moderate positive correlations between the change-scores and an external criterion (Spearman's rho: 0.46-0.58).

[CONCLUSIONS] This study indicates that the CPCHILD Dutch version has sufficient longitudinal validity statistically and clinically in nonambulatory children with severe disabilities.