New Quality of Life Index for Patients With Inflammatory Bowel Disease

Abstract

BACKGROUND: Health-related quality of life (HR-QoL) is now a standard measure of the quality of care and is an important outcome measure in clinical trials. There are several specific HRQoL measurement tools for patients with inflammatory bowel disease. However, all of them has been designed for outpatient and stable patients and not ideal for acutely ill patients and those who have stoma. Our aim is to develop a short quality of life questionnaire (Colitis Crohn's Questionnaire) for acute inpatient setting and patients with stoma. METHODS: Based on the UK Inflammatory Disease Questionnaire 1 which has been developed and validated in 2000, we derived the Colitis Crohn's questionnaire which has 32 questions and supplementary 10 questions for stoma to reflect the wider range and frequency of symptoms in patients with inflammatory bowel disease. To ensure that the resulting questionnaire is clear to patients, we asked a small sample of patients to complete the questionnaires. We have analysed baseline questionnaires completed by the 124 participants in the COnStRUCT trial cohort group. A short form of the Colitis Crohn's Questionnaire was derived by regressing the total Colitis Crohn's questionnaire on the 32 individual items. Internal consistency was assessed by item-total correlation and Cronbach alpha. Construct Validity was assessed by comparing it with SF12 and EQ5D. RESULTS: We found that 12 items together accounted for 95% of the variation in total scores between patients: sleeping, appetite, energy level, rushing to toilet, being bloated, incomplete emptying of bowels, blood in stool, generally unwell, faecal incontinence, nocturnal diarrhoea, passing winds and effect on leisure activities. Reassuringly, none of these items had item-total correlations greater than 0.8, showing that all items added extra information and none had a single response chosen by more than 80% of patients i.e. all items give good discrimination. However two of the top 12 - faecal incontinence and passing winds have item-total correlations less than 0.2, suggesting that they may not be measuring severity. So these items are candidates for removal from the short form. Indeed, since the top 8 items together accounted for 92% of the variation in total scores, they have the potential to form the definitive short form. We have also checked construct validity against the SF12 and EQ5D. Correlations of the short form with SF12 PCS (-0.421), SF12 MCS (-0.400) and EQ5D (-0.398) were around -0.4 demonstrating good evidence of construct validity as recommended by Streiner and Norman2. Test-retest reliability and responsiveness have yet to be checked. However, it is clear that the short CCQ performs well in this population and is very likely to yield a valid and efficient short form. CONCLUSION(S): We have developed a short HRQoL measurement tool for patients with inflammatory bowel disease managed in community, hospital as well as patients with stoma. This tool has a great potential use in clinical trials and in IBD UK registry.