Incidence and Predictors of Nonalcoholic Fatty Liver Disease by Serum Biomarkers in Patients with Inflammatory Bowel Disease

BACKGROUND: Patients with inflammatory bowel disease (IBD) are at high risk for non-alcoholic fatty liver disease (NAFLD). Longitudinal data on incident NAFLD are lacking. We employed non-invasive methods to study incidence and predictors of NAFLD. METHODS: This was a retrospective study of IBD patients without known liver disease followed at IBD clinic of McGill University. NAFLD was defined as Hepatic Steatosis Index (HSI) ≥36 and absence of alcohol intake. Advanced liver fibrosis was diagnosed by FIB-4 ≥2.67. Active IBD was defined as partial Mayo score ≥3 for ulcerative colitis, Harvey Bradshaw Index ≥ 5 or flare during follow-up. Kaplan-Meier and Cox regression analyses were used to investigate incidence and predictors of NAFLD development. RESULTS: Three hundred twenty-one consecutive patients (median age 33.7 yr, 47% males) were observed for a median of 3.2 years (interquartile range 1.5-6). Over 1181.2 persons-year (PY), 108 (33.6%) patients developed NAFLD, accounting for an incidence rate of 9.1/100 PY (95% confidence interval [CI], 7.4-10.9). 7 (2.2%) patients developed advanced liver fibrosis, accounting for an incidence rate of 0.5/100 PY (95% CI, 0.2-1.1). Development of NAFLD was predicted by disease activity (adjusted hazard ratio [aHR] = 1.58; 95% CI, 1.08-2.33, P = 0.02), disease duration (aHR = 1.12; 95% CI, 1.03-1.23, P = 0.01), and prior surgery for IBD (aHR = 1.34; 95% CI, 1.04-1.74, P = 0.02). CONCLUSIONS: NAFLD is a frequent comorbidity in patients with IBD. These patients can also develop advanced liver fibrosis. Disease activity, duration of IBD and prior surgery are predictors of NAFLD development. This should represent one more incentive to achieve and maintain early clinical remission. Further prospective studies are of interest.