Introduction Collagenous colitis (CC) causes chronic, watery diarrhoea.1 Bile acid malabsorption (BAM) often accompanies CC2,3 and CC can respond to treatment with BA sequestrants.4 The European Microscopic Colitis Group (EMCG) advises that BAM should be sought in investigation for CC.1 The selenium-labelled homocholic acid-taurine (SeHCAT) test is considered the gold standard for BAM diagnosis; however, serum 7 alpha-hydroxy-4-cholesten-3-one (7 aC) is simpler and less expensive, with comparable sensitivity.5 Faecal calprotectin (FC) is well-established as a biomarker of bowel inflammation, but data in CC is scant.6 We present data from a tertiary referral centre on 7 aC and FC in patients with CC.
Methods Pathology records were interrogated for patients diagnosed with CC (2000–2015), extracting results on 7 aC and FC. Results are presented as mean (±SD) or median (range).
Results Over 15 years, 399 patients were diagnosed with CC (280 F/119 M). Of these, 164 were excluded from further analysis due to lack of appropriate data. 7 aC was available in 83 (20.8%) patients, mean levels of 11.5 ± 9.70 ng/ml. 11/83 (13.3%) patients had elevated 7 aC . FC levels were measured in 101 (25.3%) patients, mean levels 251.89 ± 282.62 µg/g. Of these, 76/101 (75.2%) had elevated FC ≥ 50 µg/g (FC ≥ 100 µg/g: 63/101; FC ≥ 200 µg/g: 30/101). Of the 101 patients with FC measurement, 76 had FC results ± 30 days from the point of histological diagnosis. In this group, median FC was 165 µg/g, range 20–1375 µg/g.
Conclusion This is the first cohort data on 7 aC in CC. Our findings confirm that a significant proportion of CC patients have co-existing BAM; however, the incidence is lower than that reported in other studies using SeHCAT. The high incidence of raised FC in our cohort supports the position that FC is a useful marker of histologic inflammation in CC.
References 1 Münch A, et al. Microscopic colitis: current status, present and future challenges: statements of the European Microscopic Colitis Group. J Crohns Colitis. 201;6:932–45.
2 Wildt S, et al. Bile Acid Malabsorption in Patients with Chronic Diarrhoea: Clinical Value of SeHCAT Test. Scand J Gastroenterol 2003;38:826–30.
3 Fernández-Bañares F, et al. Bile acid malabsorption in microscopic colitis and in previously unexplained functional chronic diarrhea. Dig Dis Sci 2001;46:2231–8.
4 Münch A, Langner C. Microscopic colitis: clinical and pathologic perspectives. Clin Gastroenterol Hepatol 2015;13:228–36.
5 Brydon W G, et al. An evaluation of the use of serum 7-alpha-hydroxycholestenone as a diagnostic test of bile acid malabsorption causing watery diarrhea. Can J Gastroenterol 2011;25:319–23.
6 Wildt S, et al. Metabolic and inflammatory faecal markers in collagenous colitis. Eur J Gastroenterol Hepatol 2007;19:567–74.
Disclosure of Interest None Declared