P0698 Early faecal calprotectin predicts clinical outcomes in Acute Severe Ulcerative Colitis: results from PREDICT-UC

Abstract

Listen

Translate article

Abstract Background Faecal calprotectin (FCP) is routinely used in the management of inflammatory bowel disease; however, its role in acute severe ulcerative colitis (ASUC) is unclear. We aimed to evaluate the relationship between FCP and outcomes in ASUC. Methods We included ASUC patients who were screened/randomised as part of PREDICT-UC (NCT02770040), a randomised controlled trial that evaluated escalated infliximab (IFX) dosing strategies in steroid-refractory ASUC.1 Stool was collected at screening, and in steroid-refractory patients at day 0 (pre-IFX), and days 1, 3, 5, 7, 14, 30 and 42 and months 3, 6, 9 and 12 post-IFX. FCP was quantified by Liaison® XL (Diasorin) and correlated with outcomes. Outcomes included initial IFX response by day 7 (Lichtiger score<10, with ≥3-point reduction and decrease in rectal bleeding and stool frequency ≤4/day), month 3 colectomy and month 3 Mayo remission (partial Mayo ≤1 & Mayo endoscopic score ≤1). Results Of 185 patients with ASUC, 49 were steroid responders while 136 were steroid-refractory and received IFX. Of 136, 85 were initial IFX responders and 17 required colectomy by month 3. Screening FCP was higher in steroid-refractory compared to steroid responsive patients (median [IQR] 3745 [1753-6175] ug/g vs 2305 [826-4400] ug/g, P=0.020). In steroid-refractory patients, day 0 FCP did not correlate with the Mayo endoscopic score or Ulcerative Colitis Endoscopic Index of Severity (UCEIS) but correlated with CRP (rho=0.251, P=0.031) and the erosion/ulcer sub-score of the UCEIS (rho=0.298, P=0.010). In linear mixed modelling, FCP dynamics in the first 3 days differed between IFX responders and non-responders (daily 22% decrease [95% CI 13 to 31%] vs 3% decrease [95% CI -12 to 16%], P=0.018). A higher day 3:day 0 FCP ratio predicted initial IFX non-response (median [IQR] 109 [51-158] % vs 57 [21-92] %, P=0.006, Area under receiver operator characteristic curve [AUROC]=0.72). FCP dynamics in the first 2 weeks after IFX differed in patients who avoided vs required colectomy (weekly 59% decrease, 95% CI 52 to 65% vs 6% decrease, 95% CI -76 to 50%; P=0.012). Month 3 colectomy was predicted by a higher day 7 FCP (AUROC 0.71, 95% CI 0.49-0.92, P=0.044) and a higher day 3:day 0 FCP ratio (AUROC 0.75, 95% CI 0.58-0.91, P=0.018). Mayo remission at 3 months was predicted by lower day 14 FCP (AUROC 0.31, P=0.004) and day 14:day 0 ratio (AUROC 0.27, P=0.006). Conclusion FCP level and dynamics are novel predictors of outcomes in ASUC. Decrease in FCP by day 3 after IFX predicts initial response. Absolute day 7 FCP and early dynamics predict colectomy. Absolute day 14 FCP and FCP dynamics by day 14 predict month 3 Mayo remission and may help identify patients who may benefit from treatment optimisation.