Risk Factors for Abnormal Liver Function Tests in Patients With Ileal Pouch–Anal Anastomosis for Underlying Inflammatory Bowel Disease

Abstract

Liver involvement is common in patients with inflammatory bowel disease (IBD). However, the frequency and the significance of liver function test (LFT) abnormalities in patients with ileal pouch-anal anastomosis (IPAA) for underlying IBD have not been studied. The aim of this study was to evaluate the prevalence and to identify risk factors for abnormal LFTs in patients with IPAA and underlying IBD. All patients were identified from our prospectively maintained Pouchitis Database between 2002 and 2008. Abnormal LFTs were classified as the following: (i) any abnormal elevation of transaminases, and/or alkaline phosphatase (ALP), and/or bilirubin; (ii) hepatitis, if there was more than twice the elevation of transaminases; and (iii) cholestatic, if there was more than 1.5 times elevation of ALP. Clinical, endoscopic, and histological variables were assessed using Cox proportional hazard models for evaluating risk for abnormal LFTs. A total of 545 IPAA patients with underlying IBD were identified from the database, of which 373 patients who had LFTs done after their pouch surgery were included. This included 346 patients with ulcerative colitis, 25 with indeterminate colitis, and 2 with Crohn's colitis before surgery. Their mean age was 45.9+/-13.8 years. A total of 65 patients (17.4%) (40 men, 25 women, median age: 47 years) had abnormal LFTs. Of the patients, 52 (13.9%) had abnormal transaminases, whereas 15 (4%) were classified as having hepatitis. Thirty-five (9.4%) patients had an abnormal ALP level, with 18 (4.8%) classified as cholestatic. The most common cause of an abnormal LFT was transient elevation in 32 (49.2%) patients, followed by fatty liver (fatty change on imaging with body mass index (BMI) > or =25 kg/m(2) in the absence of other causes, including alcohol abuse and drug-induced hepatitis) in 10 (15.4%), drug-induced abnormal LFTs in 7 (10.7%), and chronic hepatitis B or C in 6 (9.2%). Primary sclerosing cholangitis (PSC) was responsible for abnormal LFTs in 10 patients (15.4%). Cox proportional hazard model analysis showed that BMI (hazard ratio (HR)=1.07, 95% confidence interval (95% CI): 1.02, 1.12; P=0.003), the presence of PSC (HR=4.49, 95% CI: 1.45, 13.89; P=0.009), autoimmune disorder (HR=2.54, 95% CI: 1.09, 5.93; P=0.031), a family history of IBD (HR=2.32, 95% CI: 1.29, 4.17; P=0.005), and extensive colitis before colectomy (HR=4.59, 95% CI: 2.04, 10.33; P<0.001) predicted any abnormal LFTs. Abnormal LFTs were common in patients with IPAA in this cohort. The presence of co-existing autoimmune disorder, a family history of IBD, extensive colitis before colectomy, the presence of PSC, and a high BMI appear to be a significant risk factors for abnormal LFTs. Whether abnormal LFTs affect health-related quality of life, pouch survival, and selection of pouch-related medical therapy requires further investigation.