Prevalence and risk factors of nonalcoholic fatty liver disease in patients with inflammatory bowel diseases: A cross-sectional and longitudinal analysis

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is common in the German population, with an even higher prevalence in inflammatory bowel disease patients. AIM: To investigate the risk factors for NAFLD in inflammatory bowel disease patients. METHODS: This monocentric retrospective study with a cross-sectional and a longitudinal part included 694 patients. Inclusion criteria were diagnosed inflammatory bowel disease, age ≥ 18 years, availability of at least one abdominal ultrasound. Patients with infectious or suspected alcoholic fatty liver disease were excluded. NAFLD was defined by increased echogenicity at liver ultrasound. Demographic characteristics, disease activity and medications were analyzed as potential risk factors. Parameters influencing the course of NAFLD were identified by a generalized linear mixed model. RESULTS: Forty-eight percent of Crohn’s disease (CD) patients and 44% of ulcerative colitis patients suffered from NAFLD. Its occurrence was associated with greater age, hypertension and body mass index (BMI) in both groups, and with higher disease activity and dyslipidemia in CD. 2467 ultrasound results were included in the longitudinal analysis. Risk factors for NAFLD were age, BMI, higher disease activity, bowel resection(s), endoscopic activity and azathioprine use in CD; and BMI and endoscopic activity in ulcerative colitis. CONCLUSION: NAFLD was highly prevalent in this cohort of German inflammatory bowel disease patients. Its risk increased mainly with rising age and BMI. This analysis provides a rationale for non-invasive liver screening in inflammatory bowel disease patients.