THU0374 A Longitudinal Study of Gut Inflammation and The Development of Inflammatory Bowel Disease in Ankylosing Spondylitis
Authors: E. Klingberg, H. Strid, A. Ståhl, A. Deminger, H. Carlsten, L. Öhman, H. Forsblad-d'Elia
Journal: Annals of the Rheumatic Diseases (2016)

<h3>Background</h3> Patients with ankylosing spondylitis (AS) have an increased risk of developing inflammatory bowel disease (IBD). There is however a lack of knowledge regarding the incidence of IBD in AS and what predicts the development from subclinical gut inflammation to IBD. <h3>Objectives</h3> To determine the intra-individual variation in fecal calprotectin (FC) over 5 years in relation to AS disease activity, disease manifestations and medication and to study the 5–year incidence of IBD in AS and identify predictors for its9 development. <h3>Methods</h3> At baseline FC was assessed in 204 AS patients (NY-criteria) without diagnosed IBD. FC was then reexamined in 164 of the patients at the 5-year follow-up. The patients answered questionnaires regarding gastrointestinal symptoms, medication, physical function and disease activity. Ileocolonoscopy was performed at the 5-year follow-up if FC remained ≥200 mg/kg after 3 weeks NSAID-pause. The medical records were checked for colonoscopies, episodes of gut inflammation or diagnose of IBD during the follow-up period. <h3>Results</h3> The characteristics of the 164 AS patients [median (IQR)]: 74♀/90♂, age 54 (46–67) ys, symptom duration 27 (18–39) ys, BASDAI 3.2 (1.8–5.2), ASDAS<sub>CRP</sub> 2.1 (1.3–2.7), BASFI 2.3 (1.0–4.1) and BASMI 3.4 (2.4–4.6). At the 5-year follow-up FC was elevated (&gt;50 mg/kg) in 63% of the patients, but not associated with gastrointestinal symptoms. In 24% of the patients FC was &gt;200 mg/kg. The intra-individual variation in FC during the 5-year follow-up was less than ±200 mg/mg in 80% (131/164) of the patients. FC was correlated with CRP (r<sub>S</sub>=0.219; p=0.005), ESR (r<sub>S</sub>=0.172; p=0.027), ASDAS<sub>CRP</sub> (r<sub>S</sub>=0.207; p=0.008), hemoglobin (r<sub>S</sub>=-0.200; p=0.01), BASMI (r<sub>S</sub>=0.207; p=0.008) and BASFI (r<sub>S</sub>=0.154; p=0.048). Users of NSAIDs had higher FC than non-users [93 (44–215) vs. 40 (23–120) mg/kg; p=0.011], whereas DMARD users had lower FC than non-users [45 (29–87) vs. 110 (40–250) mg/kg; p&lt;0.001]. Users of infliximab, adalimumab and golimumab had lower FC than non-users [48 (23–135) vs. 89 (40–210) mg/kg; p=0.022], whereas users of etanercept had higher FC [200 (93–555) mg/kg]. In linear regression DMARD-use (B= -111.6, SE=41.0, p=0.007) and BASMI (B=41.9, SE=10.7, p&lt;0.001) remained independently associated with log-transformed FC. Totally 1.5% (3/204) had been diagnosed with Crohns disease (CD) and 0.5% with lymphocytic colitis at the five-year follow-up. Furthermore 3% had demonstrated a picture of subclinical CD and 2% a picture of subclinical chronic colitis at ileocolonoscopy. A high FC and presence of mucus in diarrhea were the main predictors of the development of CD. <h3>Conclusions</h3> FC was elevated in approximately two-thirds of the patients both at baseline and at the five-year follow-up and positively associated with disease activity at both time points. The results supports a link between gut and joint disease in AS. Use of NSAIDs and etanercept was associated with a higher FC, whereas use of other TNF-blockers and DMARDs was associated with a lower FC. The five-year incidence of CD was 1.5%, and an elevated FC was a main predictor thereof. <h3>Disclosure of Interest</h3> None declared