Primary sclerosing cholangitis is protective against nonalcoholic fatty liver disease in inflammatory bowel disease

Nonalcoholic fatty liver disease (NAFLD) occurs with higher prevalence in patients with inflammatory bowel disease (IBD) relative to the general population, and susceptibility is related to the metabolic syndrome, as well as higher prevalence of bowel resection and gut microbiotal factors. Liver complications, including NAFLD and primary sclerosing cholangitis (PSC), contribute to treatment and prognosis of patients with IBD. However, the potential interplay of NAFLD and PSC is not well understood. We retrospectively assessed severity of steatosis and steatohepatitis in liver specimens from 49 patients with IBD only, 44 with IBD and comorbid PSC, and 30 with IBD and PSC after liver transplantation. Patients with IBD had higher prevalence of at least grade 1 steatosis (59%) than IBD and PSC (11%), or IBD and PSC posttransplant (3%) (P < .001). The average severity of steatosis was 25% ± 8% (95% confidence interval) for IBD only, 3% ± 1% for comorbid IBD and PSC, and 1% ± 1% for IBD and PSC posttransplant (P < .001). Steatohepatitis was significantly higher in IBD only (12%) than in IBD and PSC ± transplant (0%) (P = .01). Despite these differences in susceptibility to NAFLD, the 3 populations had statistically indistinguishable average body mass index and total cholesterol and prevalence of hypertension, diabetes, and alcohol use. Multivariate regression modeling revealed body mass index, hypertension, and diabetes as significant correlates to NAFLD severity in all studied populations. In conclusion, patients with comorbid IBD and PSC have significantly less susceptibility to NAFLD than those with IBD alone, despite similar prevalence of major NAFLD risk factors.