An International Multicenter Comparison of IBD-Related Disability and Validation of the IBDDI.

Background: The IBD disability index (IBDDI) has been shown to be valid and reliable. We compared the distributional and predictive properties of the IBDDI, when collected from five populations of people living with IBD- from Winnipeg, Chicago, Toronto, Hong Kong, and Jerusalem.

Methods: People with IBD from five jurisdictions were invited to complete a survey including the IBDDI, the World Health Organization Disability Assessment Scale, the Work and Social Adjustment Scale, the IBDQ, the Kessler-6 distress scale, and the Stanford presenteeism scale. Between sites, we compared the correlation between IBDDI and the other 4 measures of disability/quality of life/distress, and the association between IBDDI and presenteeism and having been hospitalized in the past year.

Results: There were 1121 participants from Winnipeg, 511 from Chicago, 147 from Toronto, 97 from Hong Kong, and 96 from Jerusalem. The majority had Crohn's disease. Although the mean IBDDI score varied by site, the correlation between IBDDI and each of the other 4 measures of disability/QOL/distress was nearly identical. Similarly, the regression coefficient showing the association between IBDDI and presenteeism was nearly identical in all sites, and the risk ratios showing the association between hospitalization and high IBDDI was similar in all sites.

Conclusion: The correlation between IBDDI and different measures of disability/QOL/distress was similar across all sites. There is strong evidence of the association between IBD-related disability and presenteeism, and between hospitalization and high IBD-related disability, and that the associations are the same across different populations. The severity of disability that an individual with a given IBDDI score has is directly comparable across populations.