P271 Bile acid malabsorption does not cause a low faecal elastase

Abstract

Introduction The coordination of biliary and pancreatic secretions is vital for normal digestion. However, it is unknown if bile acid malabsorption (BAM) is associated with pancreatic exocrine insufficiency (PEI). Faecal elastase-1 (FE1) is the only widely available test for PEI. Its limitations include a falsely low (positive) result in patients submitting dilute stool samples, as might occur in patients with BAM. We studied the association between BAM and PEI, and the impact of coexisting BAM on the management of patients with low FE1. Methods We carried out a retrospective study at a London teaching hospital. All outpatients investigated with both FE1 and a SeHCAT scan between 2012 and 2018 were identified. Demographic and clinical information was retrieved from the electronic medical record. PEI was defined as FE1 Results 258 patients were identified; mean age 51 years; 65.5% female; 61.6% white ethnicity. BAM was diagnosed in 111 patients (43%). PEI was diagnosed in 39 patients (15.1%), with no subjective difference between those with and without BAM (15.3 v. 15.0%). On univariable analysis, BAM was not associated with PEI (OR 1.03; 95% CI 0.52 to 2.04; p=0.94). After adjusting for age, sex and ethnicity, this lack of association held (OR 0.78; 95% CI 0.37 to 1.64; p=0.52). 43 patients (16.7%) had FE1 repeated, with 9 patients (20.9%) reclassified from PEI to normal as a result. There was no difference between patients with and without BAM in FE1 being repeated (15.3% v. 17.7%; p=0.61) or the repeat FE1 leading to reclassification of PEI status (23.5% v. 19.2%; p=0.74). In patients with PEI, there was no difference in the rate of pancreatic imaging between those with and without BAM (64.7% v. 63.6%; p=0.61), but pancreatic abnormalities were detected more frequently in patients with coexisting BAM (58.3% v. 20.0%; p=0.04). Findings included atrophic or fatty pancreas, and one pancreatic cancer. There was a non-significant trend towards fewer patients with PEI and BAM receiving PERT (58.8% v. 72.7%; p=0.36), but no difference in clinical response when treated (77.8% v. 76.9%; p=0.96). Conclusions BAM is not associated with PEI. However, when a patient with BAM does have a low FE1, our findings suggest most are representative of PEI, rather than false positives.