WHICH IS IMPORTANT? GLUTEN FREE DIET OR INFLAMMATORY BOWEL DISEASE MEDICATIONS IN SUBJECTS WITH AN OVERLAP WITH CELIAC DISEASE AND INFLAMMATORY BOWEL DISEASE: OBSERVATIONS FROM A CASE SERIES AT A LARGE ACADEMIC CENTER
Authors: Montrose Jonathan , Montalvan-Sanchez Eleazar , Billings Wade , Walker Megan , Bohm Matthew , Sagi Sashidhar , Fischer Monika , Kurada Satya 
Published: January 2023

Abstract

INTRODUCTION
Celiac disease (CeD) and inflammatory bowel disease (IBD) are autoimmune diseases of the bowel with similar clinical symptoms. This study aims to characterize the clinical course of both diseases in subjects with overlap of CeD and IBD (CeD+IBD) on a gluten free diet (GFD) and IBD medications.

METHODS
We conducted a retrospective study of demographic and serological characteristics in subjects with CeD+ IBD at a large academic center using appropriate International Classification of Disease (ICD)-10 codes from 2017 to June 2022.

RESULTS
36 subjects had IBD +CeD. 96% of subjects were Caucasian and 67% were female. The diagnosis of CeD post-dated the diagnosis of IBD by 3.6 years. Ulcerative colitis (UC) and Crohn’s disease (CD) occurred equally in IBD +CeD. About 75% of subjects had L2+L3, B1 phenotype per Montreal classification. 44% of UC +CeD subjects had pancolitis with 72% of them being classified as S0 (never severe) per Paris classification. 83% of subjects initiated a self-taught GFD. Only 17% of subjects sough advice from a celiac dietician. Mean duration at which GFD was initiated was 0.7 yrs from the initial diagnosis of CeD. Only 1/36 subjects followed a strict GFD during 6.5 years of follow up. The second and third assessment of GFD happened after a mean of 3.7 yrs and 5.2 yrs from the time of initiation of a GFD with only 1/36 subjects adhering to a strict GFD at these time points. Serum tTG IgA levels were tested on average at 4, 91, 154, 186 and 192 weeks from the diagnosis of CeD, with a consistent drop in mean tTG IgA titers to 45, 33, 19, 25 and 4 respectively. Only 1 subject got tTG IgA measurements over the next 250 weeks of follow up. Over a 10.1 year follow up since the diagnosis of IBD, descending proportions of subjects needing IBD medications were as follows: topical 5-ASA (aminosalicyates) (19/36)&gt;oral steroids (18/36)&gt; anti-TNF (tumor necrosis factor) (18/36)&gt; anti-integrins (12/36)&gt; azathioprine (10/36)&gt; anti-IL12/23 (8/36)&gt; topical 5-ASA (4/36)&gt; MTX (methotrexate) (5/36)&gt; topical steroids at 2/36. Mean time to initiation of IBD medications (in weeks) after GFD initiation as a reference point were in an order of oral 5-ASA (-67) &lt; anti-TNF (-39) &lt; AZA (-14) &lt;MTX (-6) &lt; topical 5-ASA (-2) &lt;oral steroids (82) &lt;anti-integrins (124) &lt;anti-IL 12/23 (137)

CONCLUSIONS
Majority of subjects depended on a self-educated GFD. A small proportion of CeD +IBD subjects were assessed per clinical guidelines with respect to adherence to a GFD, serology. At least 50% of subjects with CeD+IBD needed escalation of IBD treatment to biologics and/or steroid rescue over 10 years despite initiation of GFD (albeit suboptimal). We need to further substantiate these findings with exclusive IBD and celiac control groups. We suggest establishing CeD centers at tertiary hospitals for adequate clinical guideline adherence.