Systematic review and meta-analysis: assessment of factors affecting disability in inflammatory bowel disease and the reliability of the inflammatory bowel disease disability index

Background: The Inflammatory Bowel Disease Disability Index (IBD-DI) has recently been developed for patients with Crohn's disease (CD) and ulcerative colitis (UC). Aim: To assess the severity of disability and associated factors using the IBD-DI, and review the validity of the IBD-DI as a tool. Method: Systematic review of cross-sectional studies. Patients included had UC or CD and were classified as active, in remission, or needing surgery, biological and/or steroid treatment. We included studies assessing disability using the IBD-DI and that were captured by electronic and manual searches (January 2017). The possibility of bias was evaluated with the Newcastle-Ottawa Scale. Results: Nine studies were included with 3167 patients. Comparatively, patients with active disease had higher disability rates than those in remission (SMD [CI95] = 1.49[1.11, 1.88], I² = 94%, P<.01), while patients on biological treatment had lower disability rates than those receiving corticosteroid treatment (SMD [CI95] = −0.22[−0.36, −0.08], I² = 0%, P<.01). Disease activity and unemployment were found to be associated factors. The IBD-DI scored “good” for internal consistency, “fair” to “excellent” for intra-rater reliability and “excellent” for inter-rater reliability. Construct validity was “moderately strong” to “very strong” and structural validity was found to be mainly unidimensional. The IBD-DI had excellent responsiveness, while its interpretability was only useful on a group level. Conclusions: This systematic review and meta-analysis found a significant association between disease activity, treatment received and disability; although significant heterogeneity was found. The IBD-DI is reliable and valid, but further studies are needed to measure its interpretability.