Objective: Clinimetric evaluation of the Dutch version of the Functional Status II(R) (FS II), measuring children's behaviour and the effect of disease on it.
Design: Descriptive.
Setting: University of Utrecht, department of General Practice Medicine, and Julius Centre for Patient-linked Research.
Methods: Parents of children (6 months-11 years of age) with or without asthma were questioned using the Dutch translation of the FS II. Parents of children with asthma and of control children were questioned again using the FS II after 24 hours and after one month. A child version of the FS II, developed by our group, was used for children between 8 and 12 years of age. We tested internal consistency, test-retest reliability, discriminant validity, sensitivity to parents' opinion on presence or absence of health complaints and agreement between the parent and the child version.
Results: The group included 124 parents of asthmatic children and 224 parents of control children, 111 of whom were aged 8-12 years. The parent version of the FS II showed good reliability and validity. Cronbach's alpha, measuring internal consistency, was between 0.66 and 0.90, and the 24-hour test-retest reliability was between 0.83 and 0.92. FS II-scores of children with asthma were significantly lower than those of children in the control group, and scores of children with health complaints were significantly lower than those of children without any health complaints, cross-sectionally as well as longitudinally. Reliability and validity figures of the child version of the FS II were far behind those of the parent version. Scores on the child version were only weakly related to those on the parent version.
Conclusion: The parent version of the Dutch FS II is recommended as a generic measure of functional health status of children for medical research. The child version should be improved first.