Factors associated with development of NAFLD in patients with inflammatory bowel disease: a 5-year retrospective study on 225 patients

Background Patients with IBD are at higher risk for non- alcoholic fatty liver disease (NAFLD) comparing to general population. Complex pathogenesis of NAFLD in IBD may be related to disease-specific risk factors such as chronic inflammation, steroid exposure, drug induced hepatotoxicity, malnutrition and alteration of gut microbiota, which is emerging as a major factor in the pathogenesis of NAFLD. The goal of the study was to investigate factors associated with NADLF and advanced liver fibrosis (ALF) in patients with CD and UC. Methods This is a retrospective study on IBD patients without extraintestinal manifestations and known liver disease. NAFLD was defined as Hepatic Steatosis Index (HSI) ≥ 36, and ALF was defined as FIB-4 ≥ 2.67. Predictors of NAFLD development were analysed using Kaplan–Meier and Cox regression analyses. Results In this retrospective study, we have included 225 IBD patients ; 72.4% (n = 163) patients with CD and 27.6% (n = 62) patients with UC (median age 41.2 yr, 53.7% males) which were observed for a median of 4.6 years. There were 63.1% (n = 142) patients with normal BMI, 27.6% (n = 62) overweight and 9.3% (n = 21) obese patients. Obese patients had the highest HIS score 43.9 ± 5.9, following with overweight 37.8 ± 5.7 and normal BMI 30 ± 4.3 kg/m2, p < 0.001. During the follow-up obese and overweight patients had higher risk of developing NAFLD comparing to patients with normal BMI (obese HR = 11.1 95% CI 4.3–28.3 and overweight HR = 5.55 95% CI 3.4–9.1, Logrank test p < 0.001) (Figure 1). Regarding FIB-4 score there, was no difference among different BMI categories (p = 0.192), and there was no difference in ALF development in the follow-up period (Logrank test p = 0.91). In Cox proportional-hazards regression significant predictors for NAFLD development were dyslipidaemia HR=2.11, 95% CI 1.2– 3.7, overweight HR=6 95% CI 3.6–10, and obesity HR=13.4, 95% CI 7– 35. graphic Conclusion NAFLD is frequent comorbidity in patients with CD and UC, which can lead to development of advanced liver fibrosis. Our results show that patients with IBD have a high risk of NAFLD development, whereas the increased risk for ALF was not observed. Overweight and obese patients and those with dyslipidemia should be closer monitored due to significantly higher risk of NAFLD. This study points out the complexity disease-specific risk factors and importance of better stratifying IBD patients at risk of NAFLD and advanced liver fibrosis.