Association of non-alcoholic fatty liver disease with gallstone disease in the United States hospitalized patient population

BACKGROUND: Gallstones and cholecystectomy have been proposed as risk factors for non-alcoholic fatty liver disease (NAFLD). The reason for this may be that both gallstones, as well as NAFLD share several risk factors with regards to their development. Currently, there is a lack of sufficient evidence showing an association between these clinical conditions. AIM: To determine whether there is a meaningful association between gallstones and cholecystectomy with NAFLD. METHODS: We queried the National Inpatient Sample database from the years 2016 and 2017 using International Classification of Diseases, 10(th) revision, Clinical Modification diagnosis codes to identify hospitalizations with a diagnosis of gallstone disease (GSD) (includes calculus of gallbladder without cholecystitis without obstruction and acquired absence of gallbladder) as well as NAFLD (includes simple fatty liver and non-alcoholic steatohepatitis). Odds ratios (ORs) measuring the association between GSD (includes gallstones and cholecystectomy) and NAFLD were calculated using logistic regression after adjusting for confounding variables. RESULTS: Out of 14294784 hospitalizations in 2016-2017, 159259 were found to have NAFLD. The prevalence of NAFLD was 3.3% in patients with GSD and 1% in those without. NAFLD was prevalent in 64.3% of women with GSD as compared to 35.7% of men with GSD. After controlling for various confounders associated with NAFLD and GSD, multivariate-adjusted analysis showed that there was an association between NAFLD with gallstones [OR = 6.32; 95% confidence interval (CI): 6.15-6.48] as well as cholecystectomy (OR = 1.97; 95%CI: 1.93-2.01). The association between NAFLD and gallstones was stronger in men (OR = 6.67; 95%CI: 6.42-6.93) than women (OR = 6.05; 95%CI: 5.83-6.27). The association between NAFLD and cholecystectomy was stronger in women (OR = 2.01; 95%CI: 1.96-2.06) than men (OR = 1.85; 95%CI: 1.79-1.92). P value was less than 0.001 for all comparisons. CONCLUSION: NAFLD is more prevalent in women with GSD than men. The association between NAFLD and cholecystectomy/gallstones indicates that they may be risk factors for NAFLD.