Health related quality of life in disorders of defecation: the Defecation Disorder List

BACKGROUND

Constipation and encopresis frequently cause problems with respect to emotional wellbeing, and social and family life. Instruments to measure Health Related Quality of Life (HRQoL) in these disorders are not available.

METHODS

A disease specific HRQoL instrument, the "Defecation Disorder List" (DDL) for children with constipation or functional non-retentive faecal soiling (FNRFS) was developed using accepted guidelines. For each phase of the process, different samples of patients were used. The final phase of development included 27 children. Reliability was assessed in two ways: internal consistency of domains with Cronbach's alpha, and test-retest reliability with intra-class correlation coefficients (ICC). To assess validity, comparable items and domains were correlated with Tacqol, a generic HRQoL instrument for children (TNO-AZL).

RESULTS

In the final phase of the development, 27 children completed the instrument. It consisted of 37 items in four domains. The response rate was 96%. Reliability was good for all domains, with Cronbach's alpha values ranging from 0.61 to 0.76. Measures of test-retest stability were good for all four domains with ICCs ranging from 0.82 to 0.92. Validity based on comparison with the Tacqol instrument was moderate.

CONCLUSION

The DDL is promising as a measure of HRQoL in childhood defecation disorders.

A comparison of Likert scale and visual analogue scales as response options in children's questionnaires

AIM

To examine which response options children prefer and which they find easiest to use, and to study the relative reliability of the different response options.

METHODS

A consecutive group of unselected children (n = 120) filled out three questionnaires in a paediatric outpatient clinic. Each questionnaire included seven similar questions, but had different response options: the Likert scale, the Visual Analogue Scale (VAS) and the numeric VAS. In general, the questions were not related to the children's particular diseases, but dealt with the frequency of simple activities, their feelings and opinions. The pages with the three different response options were offered in random order. Afterwards, the children rated their preference and ease of use of the different response options on a scale from one to 10.

RESULTS

Children preferred the Likert scale (median mark 9.0) over the numeric VAS (median mark 8.0) and the simple VAS (median 6.0). They considered the Likert scale easiest to fill out (median mark 10 vs 9 and 7.5 for the numeric and simple VAS, respectively). Results of the different response options correlated strongly with each other (rho = 0.67-0.90, p < 0.05).

CONCLUSION

Children prefer the Likert scale over the numeric and simple VAS and find it easiest to complete. The Likert scale, the simple VAS and the numeric VAS are of comparable reliability. The Likert scale is recommended for use in questionnaires for children, although research into larger and more diverse samples is needed.

Measuring quality of life in children with inflammatory bowel disease: the impact-II (NL)

Inflammatory bowel disease (IBD) is a chronic debilitating disorder. Measures of quality of life are only available for adult patient populations. We developed a new disease-specific health-related quality of life instrument in Dutch for pediatric patients with IBD, called Impact-II (NL). We translated and strongly modified the original (Canadian) Impact questionnaire. It comprises 35 items in six domains. Eighty-three children (66%) completed the questionnaire, 39 children were assessed twice. Disease symptoms were recorded and disease course severity assessed through chart review. Summated disease activity scores and disease course severity scores were dichotomized into two categories. Reliability coefficients were good for five out of six domains (Cronbach's alpha ranged from 0.57 to 0.86) and measures of test-retest stability in clinically stable patients were good for all domains (intra-class correlation coefficients ranged from 0.67 to 0.91). The instrument showed good discriminant validity between symptom groups and disease course severity on all domains. Convergent validity with a validated generic instrument [TNO-AZL Children's Quality of life questionnaire (Tacqol)] showed satisfactory coefficients. In conclusion, the developed questionnaire shows good psychometric properties. Test-retest stability and responsiveness to change should be further assessed in larger patient samples. Cross-cultural translation and validation procedures into other languages are being conducted to enable international use of Impact-II.