Impact of Bariatric Surgery on Outcomes of Patients with Non-alcoholic Fatty Liver Disease: A Nationwide Inpatient Sample (NIS) Analysis, 2004-2012

Abstract

Introduction: Morbid obesity is strongly associated with non-alcoholic fatty liver disease (NAFLD). Recent studies suggest that bariatric surgery in morbidly obese individuals that have failed to lose weight through lifestyle modifications can improve liver steatosis, inflammation, and fibrosis. However, population-based studies on the long-term benefits of bariatric surgery in NAFLD patients are lacking. We investigated the effect of bariatric surgery on clinical (hepatic and extra-hepatic) outcomes in hospitalized patients with NAFLD. Methods: The NIS database, the largest all-payer inpatient database in the United States, was queried for all eligible inpatient admissions from 2004 to 2012 with a co-diagnosis of NAFLD and morbid obesity. A history of prior-bariatric surgery (Roux-en-Y, gastric band, and sleeve gastrectomy) was identified using International Classification of Disease, 9th Revision, Clinical Modification (ICD-9-CM) codes. The primary outcome was in-hospital mortality. Secondary outcomes included liver cirrhosis, myocardial infarction, renal failure, and stroke. Poisson regression was used to determine incident risk ratios (IRR) for clinical outcomes in patients with prior-bariatric surgery compared to those without bariatric surgery. Results: Among a total of 45,474 patients (female: 69.1%; 47.4±13.1 years; white 72.5%), with a discharge diagnosis of NAFLD and morbid obesity, 18,625 patients (40.96%) had prior-bariatric surgery. Figure 1 shows the trends of discharges with prior-bariatric surgery. On multivariate analysis, as compared to no bariatric surgery, prior-bariatric surgery was associated with decreased inpatient mortality (IRR=0.08; 95% CI, 0.03-0.20, p < 0.001). Prior-bariatric surgery was also associated with signifi cantly lower rates of liver cirrhosis, myocardial infarction, renal failure, and stroke (All p < 0.001, Table 1).Figure 1Table 1: Prior-bariatric surgery and association with cirrhosis, myocardial infarction, renal failure, and strokeConclusion: Bariatric surgery may mitigate hepatic and extrahepatic complications of NAFLD, including morbidity and mortality, among morbidly obese NAFLD patients. However, the decline in uptake of bariatric surgery among NAFLD patients in recent years (2004 to 2012) highlights the need for other less invasive and effective treatments options (e.g. intra-gastric balloons) in NAFLD patients who fail to lose weight through lifestyle modifications.