Coeliac disease bidirectionally linked to IBD

A two-way association exists between coeliac disease (CeD) diagnosis and inflammatory bowel disease, which demands attention in the initial assessment and follow-up of such conditions, according to a study. Regardless of temporal sequence, this co-occurrence indicates a shared aetiology.

The investigators identified 48,551 patients with CeD and 83,529 with IBD diagnosed in 1969‒2016 using Swedish histopathology and healthcare register data. They compared each patient with age- and sex-matched comparators in the general population (CeD: n=240,136; IBD: n=408,195).

Cox regression was used to estimate hazard ratios (HRs) for IBD in patients with CeD and vice versa. To reduce surveillance bias, the main analyses were limited to events beyond the first year of follow-up.

A total of 784 (1.6 percent) patients with CeD were diagnosed with IBD relative to 1,015 (0.4 percent) matched comparators during follow-up. The HR for IBD in CeD patients was 3.91 (95 percent confidence interval [CI], 3.56‒4.31), with similar HRs for Crohn’s disease (4.36, 95 percent CI, 3.72‒5.11) and ulcerative colitis (3.40, 95 percent CI, 3.00‒3.85).

On the other hand, 644 (0.8 percent) IBD patients and 597 (0.1 percent) comparators were diagnosed with CeD during follow-up. The HR for CeD in IBD patients was 5.49 (95 percent CI, 4.90‒6.16). The highest risk estimates were noted in ulcerative colitis (HR, 6.99, 95 percent CI, 6.07‒8.05), while the HR for Crohn’s disease was 3.31 (95 percent CI, 2.69‒4.06).

The diagnostic interval in CeD and IBD patients was <1 year usually, but HRs of 3‒4 were seen even after 10 years of follow-up. Over 20 years of follow-up, 2.5 percent of CeD patients developed incident IBD and 1.3 percent of IBD patients developed CeD.