Risk factors of non-alcoholic fatty liver disease in patients with inflammatory bowel disease

Abstract

Background: Metabolic risk factors are associated with non-alcoholic fatty liver disease (NAFLD), but they are less frequent in inflammatory bowel disease (IBD).

Aim: This study evaluates the frequency of NAFLD and its risk factors among IBD patients including anti-TNF-α therapy.

Methods: IBD patients who underwent abdominal imaging from January, 2009 to December, 2010 were analyzed in this nested, case-controlled study. IBD patients with NAFLD by imaging were compared with those who had no evidence of NAFLD (control).

Results: Among 928 IBD patients, 76 (8.2%) had evidence of NAFLD by imaging, and were compared to 141 patients without NAFLD evaluated (study: control ratio=~1:2). NAFLD patients were older (46.0 ± 13.3 vs. 42.0 ±14.1 years; p=0.018) and had a later onset of IBD compared to the control group (37.2 ± 15.3 vs. 28.7 ± 23.8 years; p=0.002). Metabolic syndrome was present in 29.0% of NAFLD patients, with a median Adult Treatment Panel risk factor of 2 [Interquartile range 1,3]. Patients not receiving anti-TNF-α therapy had a higher occurrence of NAFLD (p=0.048). In multivariate analysis, hypertension (OR=3.5), obesity (OR=2.1), small bowel surgeries (OR=3.7), and use of steroids at the time of imaging (OR=3.7) were independent factors associated with NAFLD.

Conclusion: NAFLD occurred in 8.2% of the IBD population. NAFLD patients were older and had a later onset of IBD disease. IBD patients develop NAFLD with fewer metabolic risk factors than non-IBD NAFLD patients. It is also less common among patients who received anti-TNF-α therapy.

Keywords: ASA; ATP; Adult Treatment Panel; Anti-TNF-α therapy; CD; Crohn's disease; Fatty liver; HDL; IBD; Inflammatory bowel disease; LDL; MP; NAFLD; NASH; PEM; PSC; Risk factors; TG; TNF; TSH; UC; aminosalicylic acids; high density lipoprotein; inflammatory bowel disease; low density lipoprotein; mercaptopurine; non-alcoholic fatty liver disease; non-alcoholic steatohepatitis; primary sclerosing cholangitis; protein energy malnutrition; thyroid stimulating hormone; triglycerides; tumor necrosis factor; ulcerative colitis.