Significance of non-alcoholic fatty liver disease in Crohn's disease: A retrospective cohort study

Aim: The prevalence of non-alcoholic fatty liver disease (NAFLD) and Crohn's disease (CD) is increasing. The aim of our study was to evaluate the prevalence of NAFLD in patients with CD, as well as to investigate the effect of NAFLD on the disease course of CD. Methods: Our retrospective cohort study included 303 patients who underwent abdominal ultrasound for CD and NAFLD diagnosis at our center between November 2008 and October 2014. Serum C-reactive protein (CRP) level and rate of remission, defined by a score <150 on the Crohn's Disease Activity Index, were compared between CD patients with and without NAFLD, using multivariate logistic regression. The effect of NAFLD on the surgery-free interval was evaluated using Cox proportional hazards models, adjusted for potential demographic confounders. Results: Non-alcoholic fatty liver disease was diagnosed in 66 (21.8%) patients in our study cohort and was associated with lower CRP levels (0.58 vs. 2.18 mg/dL, P<0.0001) and a higher rate of remission (75.9% vs. 53.7%, P=0.0024). Non-alcoholic fatty liver disease was identified as an independent predictor of a negative CRP level (<0.3mg/dL; odds ratio, 1.85; 95% confidence interval, 1.03-3.37) and higher rate of remission (odds ratio, 2.57; 95% confidence interval, 1.21-5.80). Non-alcoholic fatty liver disease was associated with longer surgery-free interval (log-rank test, P=0.0035), with NAFLD identified as a positive predictor of surgery-free interval (P=0.0014). Conclusions: Non-alcoholic fatty liver disease may offer a protective effect in patients with CD and could be used as a prognostic marker in patients with CD.