In addition to physical symptoms associated with inflammatory bowel disease (IBD), there may be psychosocial effects (1–3). Children with IBD are more likely to have psychiatric morbidity (4) and impaired psychosocial functioning (5) than children with other chronic disorders. The World Health Organization defines health as a state of complete physical, mental, and social well-being (6). Health-related quality of life (HRQoL) research assesses how health, disease, or impairment affects physical, mental, cultural, environmental, and economic aspects of living (7). Outcome measures in IBD trials have traditionally relied on disease activity indices (8), but these measures fail to give a subjective view of the patients' experience. HRQoL instruments provide data that are meaningful to health professionals, patients, and their families (9–11). They complement information from disease activity indices and can evaluate how treatments affect patients' lives. HRQoL instruments for adults with IBD include the IBD Questionnaire (8) and the Rating Form of IBD Patients' Concerns (12), but these are unsuitable for and have not been validated in children.
The first HRQoL instrument for children with IBD (the IMPACT instrument) was developed in Canada by interviewing 82 children and adolescent subjects with IBD (13). An item reduction list was constructed from 94 issues or concerns identified by the children, in addition to 2 additional issues from the IBD Questionnaire. The 96 issues were ranked in order of importance by a further 117 Canadian children with IBD. The top 50 issues formed the 33 item IMPACT questionnaire consisting of 6 domains: bowel symptoms, body image, functional/social impairment, emotional impairment, test/treatments, and systemic impairment. The IMPACT instrument was subsequently validated in Canada (14).
A cross-cultural comparison showed a significant correlation between the concerns of British and Canadian children with IBD (15), but British and Dutch children found the original Canadian IMPACT instrument too complicated and/or upsetting. The IMPACT questionnaire was translated and adapted for Dutch children with IBD. A time scale was inserted, the questions were simplified, and the modified 35-item Dutch version of the IMPACT instrument was validated (16). Seventy-two children with IBD—41 from Canada, 11 from Amsterdam, the Netherlands; and 20 from Manchester, UK—completed the original IMPACT instrument and the modified version. Forty-two children stated a preference for one of the instruments, with 30 preferring the modified version of the IMPACT instrument (17). A Dutch study on the use of response scales (18) showed that children preferred a Likert scale because it was easier to complete than a visual analog scale (VAS). It was suggested that the IMPACT questionnaire may benefit from a Likert scale rather than a VAS.
The present study aimed to identify changes needed to adapt the IMPACT instrument for use in British children with IBD and to see whether children preferred the Likert scale or the VAS.
MATERIALS AND METHODS
The simplified Dutch version of the IMPACT instrument was translated back into English by 2 independent translators and any differences were resolved by consensus. The final resulting version (IMPACT-UK) was checked by the original Canadian developers of IMPACT, the Dutch researchers, and the present investigators to ensure that the original concepts were maintained. These researchers, which included 3 quality of life methodologists and an IBD research nurse, formed a multidisciplinary committee (including several members fluent in Dutch and English) who agreed on the methodology for validation and translation (as proposed by Guillemin et al (19)) of the IMPACT questionnaire. Although the Dutch and UK versions of the IMPACT instrument retained the original concepts of the Canadian IMPACT questionnaire, it was believed that because of the modifications described, further validation would be required in both countries.
Two versions of the IMPACT-UK instrument incorporating different response scales (VAS and Likert scale) were used to determine which scale British children preferred. The VAS consisted of a 10-cm line with 2 extreme response options at each end whereas the Likert scale had 5 discrete points. Twenty children with IBD completed both versions of the IMPACT-UK questionnaire immediately after one another in random order. They were asked which response scale they preferred and why, whether they had any difficulty understanding the questions or response options, whether they thought the questions were relevant, and how they could be improved. Four respondents had cognitive interviews and were asked to “think aloud” about their understanding of the questions and the reasons for their answers. Any words or phrases that the children had difficulty in understanding would be modified before formal validation of the IMPACT-UK instrument. To compare the Likert scale and VAS versions of the IMPACT-UK instrument, the overall mean scores and domain scores of each version were calculated and transformed. The domains had previously been identified by Loonen et al (16). The Likert scale was coded from 0 to 4 on each item (total IMPACT score, 0–140). The scores were translated to a scale of 0 to 100 by totalling all item scores for the domain, dividing by the total possible score for that domain, and then multiplying by 100. The VAS was scored by measuring the distance in millimeters between the leftmost point of the line to the respondent's mark. All item scores for the domain were added together and then divided by the total number of items in the domain. The χ2 test was used to see which scale the children preferred.
The study was approved by the Salford and Trafford Research and Ethics Committee. Children were recruited from the gastroenterology outpatient clinic at Booth Hall Children's Hospital, Manchester, UK.
Characteristics of the children who participated are shown in Table 1. All children believed all the questions were relevant. Five children (ages 8–12 years; 3 with Crohn disease, 1 with ulcerative colitis, and 1 with indeterminate colitis) had difficulty understanding certain words. They did not know what “restrictions” meant, they knew what inflammatory bowel disease was but not the abbreviation “IBD,” and they understood the word “diarrhea” when spoken aloud but could not read it as “diarrhoea.” “Moderate” was a response option in the Likert scale and some children only guessed that it meant “in the middle” because of its positioning on the scale. Participants distinguished between the responses in the Likert scale and related their answers to the response options proficiently. Eight respondents had difficulty with question 35, “Has your school been on a break during the past 2 weeks? If not, during those past 2 weeks how often could you go to school?” They thought the question was asking if their school had lunch and play breaks. By the end of the study, no new problems were being reported by the subjects, suggesting that the sample size was adequate.
Fifteen participants preferred the Likert scale because they believed it was quicker and easier to complete, whereas those who preferred the VAS believed it was more accurate. The mean overall scores for the 2 scales were similar, but there were significant differences in the body image and IBD symptom domains (Table 2).
The cross-cultural comparison by Richardson et al (15) showed that British children with IBD had similar concerns as Canadian children with IBD. The aim of this study was to identify the changes needed to adapt the IMPACT instrument for use in children with IBD in the UK and to determine the preferred response scale.
Certain words or phrases caused difficulty for some of the children. We propose the following changes to make the questionnaire more child-friendly: “restrictions” to be changed to “limits,” “moderate” to be replaced with “quite a bit,” “diarrhoea” to be followed by the explanation “loose or frequent bowel movements,” “IBD” to be replaced by “inflammatory bowel disease,” and the question about school attendance to be rephrased, “How often are you able to go to school?”
As in the previous Dutch study (18), most children preferred the Likert scale and believed it was easier to complete. It is therefore proposed to use this in the IMPACT-UK questionnaire to facilitate self-completion. Calculation of scores from a VAS is time-consuming and laborious, whereas the Likert scale options have a preassigned values, facilitating calculation of the score. The mean overall scores of both versions of the IMPACT instrument were similar, but there were significant differences in the body image and IBD symptom domains, thus confirming the need for further psychometric validation of the IMPACT-UK instrument.
The present study shows that the IMPACT instrument needs modifications in language, phrasing, and response scale for British children to fully understand the instrument and complete it by themselves. With the proposed modifications, it should be suitable for British children with IBD but further psychometric evaluation is needed to ensure that the instrument is reliable and valid. The IMPACT-UK questionnaire could then be used to assess patients in the clinical setting and as an outcome measure in clinical trials. Its development for use in the UK will also help contribute to our understanding about the effects of IBD on affected children.
The authors acknowledge the considerable help of Dr Hester van Der Zaag Loonen in the planning of this study.
1. Rabbett H, Elbadri A, Thwaites R, et al
. Quality of life of children with Crohn's disease. J Pediatr Gastroenterol Nutr 1996; 23:528–533.
2. Decker J. The effects of inflammatory bowel disease on adolescents. Gastroenterol Nurs 2000; 23:63–66.
3. Mackner LM, Sisson DP, Crandall WV. Review: psychosocial issues in pediatric inflammatory bowel disease. J Pediatr Psychol 2004; 29:243–257.
4. Engstrom I. Mental health and psychological functioning in children and adolescents with inflammatory bowel disease: a comparison with children having other chronic illness and with healthy children. J Child Psychol Psychiatry 1992; 33:563–582.
5. De Boer M, Grootenhuis M, Derkx B, et al
. Health-related quality of life
and psychosocial functioning of adolescents with inflammatory bowel disease. Inflamm Bowel Dis 2005; 11:400–406.
6. World Health Organization. Preamble to the Constitution of the World Health Organization as adopted by the International Health Conference, New York, June 19–22 Geneva: World Health Organization 1946; 2:100.
7. Ferry G. Quality of life in inflammatory bowel disease: background and definitions. J Pediatr Gastroenterol Nutr 1999; 28:S15–S18.
8. Guyatt G, Mitchell A, Irvine E, et al
. A new measure of health status for clinical trials in inflammatory bowel disease. Gastroenterology 1989; 96:804–810.
9. Abbott J, Webb K, Dodd M. Quality of life in cystic fibrosis. J R Soc Med 1997; 90:S37–S42.
10. Abbott J, Gee L. Contemporary psychosocial issues in cystic fibrosis: treatment adherence and quality of life. Disabil Rehabil 1998; 20:262–271.
11. Abbott J, Gee L. Quality of life in children and adolescents with cystic fibrosis: optimising treatments and clinical trial design. Paediatr Drugs 2003; 5:41–56.
12. Drossman D, Leserman J, Li Z, et al
. The rating form of IBD patient's concerns; a new measure of health status. Psychosom Med 1991; 5:701–702.
13. Griffiths A, Nicholas D, Smith C, et al
. Development of a quality of life index for pediatric inflammatory bowel disease: dealing with differences related to age and IBD type. J Pediatr Gastroenterol Nutr 1999; 28:S46–S52.
14. Otley A, Smith C, Nicholas D, et al
. The IMPACT questionnaire: a valid measure of health related quality of life in pediatric inflammatory bowel disease. J Pediatr Gastroenterol Nutr 2002; 35:557–563.
15. Richardson G, Griffiths A, Miller V, et al
. Quality of life in inflammatory bowel disease: a cross cultural comparison of English and Canadian children. J Pediatr Gastroenterol Nutr 2001; 32:573–578.
16. Loonen H, Grootenhuis M, Last B, et al
. Measuring quality of life in children with inflammatory bowel disease: the IMPACT-II (NL). Qual Life Res 2002; 11:47–56.
17. van der Zaag-Loonen H. The Impact of Paediatric Inflammatory Bowel Disease [Thesis]. Amsterdam: University of Amsterdam; 2002.
18. van Laerhoven H, van der Zaag-Loonen H, Derkx B. A comparison of Likert scale and visual analogue scales as response options in children's questionnaires. Acta Paediatr 2004; 93:830–835.
19. Guillemin F, Bombardier C, Beaton D. Cross-cultural adaptation of health-related quality of life
measures: literature review and proposed guidelines. J Clin Epidemiol 1993; 46:1417–1432.