Introduction
Coexistence of bile acid diarrhoea (BAD) and microscopic colitis (MC) has been described (1), and treating this with sequestrants could reduce the need for budesonide. Fasting plasma 7α-hydroxy-4-cholesten-3-one (C4) values >46 ng/mL are specific for BAD but sensitivity is only 47% (37-57%) compared with tauroselcholic [75-Se]
acid (SeHCAT) retention <10% (2). C4 values between 33 and 46 are in a diagnostic grey zone. Budesonide directly affects the bile acid homeostasis making the temporal relation between treatment and testing important. Fortunately, unlike SeHCAT testing, C4 may be sampled immediately when a patient presents with a flare of MC.
Aims & Methods
To assess the prevalence of coexisting BAD in patients with active MC.
Consequtive patients with MC and a flare fulfilling the Hjortswang diarrhoea criteria (≥3 stools or ≥1 watery stool per day) and a negative test for infectious diarrhoea were included. Patients were treated with budesonide 9 mg once daily for 6 weeks. Clinical assessment, Bristol stool charts, and fasting C4 were obtained at baseline, during the last treatment week and 4 weeks after end of treatment. Remission was defined as a daily mean of <1 watery bowel movement and <3 total bowel movements [EudraCT: 2019-002762-12].
Results
49 patients were included; 26 (53%) with collagenous colitis. Mean age was 60 (range 55-70) years, 22% current smoker, none on NSAIDs. Six (12%; 95%CI: 5–25%) of 49 patients had BAD diagnosed by C4. Another 3 patients had grey zone C4 values. Mean C4 did not change during budesonide treatment, 22 and 23 ng/mL at baseline and at week 6, respectively. SeHCAT was performed outside the study in 26 patients of whom 3 had retention of <10% and 6 of <15%. The mean total number of stools per day declined from baseline 7.9 to 1.9 and watery stools from 3.7 to 0.3 during budesonide treatment. Remission was obtained in 45. Twenty-nine had relapsed four weeks after end of budesonide treatment, 5 of 6 (83%; 95%CI: 36–100%) with MC and BAD, and 24 of 43 (56%; 95%CI: 40–71%) with MC and not BAD.
Conclusion
During an inflammatory flare of MC, 12% (5–25%) had C4-defined BAD. However, C4 only identifies about half of patients with BAD compared with the diagnostic gold standard SeHCAT, meaning about 25% of patients with MC could have coexisting BAD. Screening for BAD may have merit in MC patients with relapse of diarrhoea after budesonide treatment.
References
1 Bjørnbak C, Engel PJH, Nielsen PL, Munck LK. Microscopic colitis: clinical findings, topography, and persistence of histopathological subgroups. Aliment Pharmacol Ther. 2011, 34: 1225-34.
2. Borup C, Vinter-Jensen L, Jørgensen SPG, Wildt S, Graff J, Gregersen T, Zaremba A, Andersen TB, Nøjgaard C, Timm HB, Lamazière A, Rainteau D, Hansen SH, Rumessen JJ, Munck LK. Prospective comparison of diagnostic tests for bile acid diarrhoea. Aliment Pharmacol Ther. 2024; 59: 39-50.
Disclosure
Budesonide was donated for study use by Tillotts Pharma as an unrestricted scientific grant. Tillotts Pharma had no influence on the planning, conduct, or reporting of the study.
