Impact of bariatric surgery on outcomes of patients with nonalcoholic fatty liver disease: a nationwide inpatient sample analysis, 2004-2012.

BACKGROUND: Bariatric surgery in eligible morbidly obese individuals may improve liver steatosis, inflammation, and fibrosis; however, population-based data on the clinical benefits of bariatric surgery in patients with nonalcoholic fatty liver disease (NAFLD) are lacking. OBJECTIVES: To assess the relationship between bariatric surgery and clinical outcomes in hospitalized patients with NAFLD. SETTING: United States inpatient care database. METHODS: The Nationwide Inpatient Sample database was queried from 2004 to 2012 with co-diagnoses of NAFLD and morbid obesity. Hospitalizations with a history of prior bariatric surgery (Roux-en-Y gastric bypass, gastric band, and sleeve gastrectomy) were also identified. The primary outcome was in-hospital mortality. Secondary outcomes included cirrhosis, myocardial infarction, stroke, and renal failure. Poisson regression was used to derive adjusted incidence risk ratios for clinical outcomes in patients with prior bariatric surgery compared with those without bariatric surgery. RESULTS: Among 45,462 patients with a discharge diagnosis of NAFLD and morbid obesity, 18,618 patients (41.0%) had prior bariatric surgery. There was a downward trend in bariatric surgery procedures (percent annual change of -5.94% from 2004 to 2012). In a multivariable analysis, prior bariatric surgery was associated with decreased inpatient mortality compared with no bariatric surgery (incidence risk ratios = .08; 95% confidence interval, .03-.20, P<.001). Prior bariatric surgery was also associated with decreased incidence risk ratios for cirrhosis, myocardial infarction, stroke, and renal failure (all P<.001). CONCLUSIONS: Prior bariatric surgery is associated with decreased in-hospital morbidity and mortality in morbidly obese NAFLD patients. Despite this, the proportion of NAFLD patients with bariatric surgery has declined from 2004 to 2012.