Non-alcoholic fatty liver disease phenotypes in patients with inflammatory bowel disease

Non-alcoholic fatty liver disease (NAFLD) can be detected in up to 33.6% of inflammatory bowel disease (IBD) patients, often in absence of metabolic risk factors. Nevertheless, most of previous studies on such issue were conducted within the IBD population only. The primary aim of this study was to compare clinical and metabolic features of NAFLD in patients with and without IBD (w/o IBD) and to identify specific NAFLD phenotypes within the IBD population. Among 223 NAFLD patients, 78 patients with IBD were younger compared to 145 without (w/o) IBD, were less likely to have altered liver enzymes, had lower mean body weight, smaller waist circumference and lower body mass index (BMI); at the same time, MetS was more prevalent among patients w/o IBD (56.6 vs. 23.1%, p < 0.001). Within IBD population, patients with severe IBD showed more often severe steatosis (S3) at ultrasound (US) (32.1 vs. 16.6%, p = 0.01), compared to mild-to-moderate disease. Independent risk factors for S3 US steatosis in IBD patients at the multivariate logistic regression analysis were: more than 1 IBD relapse per year during disease history (OR 17.3, 95% CI 3.6-84), surgery for IBD (OR 15.1, 95% CI 3.1-73.7) and more extensive intestinal involvement (OR 19.4, 95% CI 3.4-110.9); the ongoing anti-Tumor Necrosis Factor alpha (antiTNF alpha) therapy was the only independent factor which protect toward the presence of altered liver enzymes (OR 0.15, 95% CI 0-0.8, p = 0.02). In conclusion, NAFLD in IBD patients is different from that in patients w/o IBD, who seem to develop different NAFLD phenotypes according to intestinal disease clinical course. More severe IBD seem to predict the presence of more severe steatosis. Therapy with antiTNF alpha antibodies could prevent alteration of liver enzymes in such population.