Bariatric surgery (BS) is a treatment option for adults with morbidity obesity, and some of these patients require close post-surgical surveillance. Surgeons sometimes perform liver biopsies to diagnose Nonalcoholic Fatty Liver Diseases (NAFLD) such as Non-Alcoholic Steatohepatitis (NASH) in this patient population. Such biopsies form the basis of a retrospective study, entitled “Non-Alcoholic Steatohepatitis (NASH): Risk Factors in Morbidly Obese Patients” and published in the International Journal of Molecular Sciences, that evaluated the prevalence of NASH and the risk factors for fibrosis in morbidly obese (MO) patients submitted to BS.

NASH is a liver inflammation caused by the accumulation of fat that ultimately leads to organ dysfunction. Because NASH is usually asymptomatic, a histopathological assessment is very important to diagnosing the disease, which often affects people between 40-50 years old who drink little or no alcohol. This current study evaluated 250 patients submitted to bariatric surgery from January 2007 to December 2012 at a reference attendance center in southern Brazil. Based on clinical and biochemical analysis of the liver biopsies obtained during surgery, researchers detected steatosis — the accumulation of lipids in liver cells — in 90.4% of the patients. NASH was diagnosed in 70.4% of patients, whereas cirrhosis was only established for 1.6% of the patients.

Fibrosis was reported in 43.2% of the biopsies, with most of them revealing mild (38%) cases, and only 7 severe cases (2.8%) detected. When associated to blood levels of alanine aminotransferase (ALT), glucose and triglycerides, the data analysis revealed that ALT >1.5 times the upper limit of normal (ULN); glucose ≥126 mg/dL and triglycerides ≥ 150 mg/dL were risk factors for NASH. In fact, all patients with ALT ≥1.5 times the ULN were diagnosed with NASH. The presence of fibrosis was associated with ALT > 1.5 times the ULN and triglycerides ≥ 150 mg/dL, identifying a subset of patients with more severe disease. Importantly, there was a 1% increase in the prevalence of fibrosis with each year of increase in the age of patients studied.

Other studies found lower values of NASH in patients with MO, which could be explained by more specific criteria. The body mass index (BMI) of patients did not correlate with a risk of NASH. “Contrary to other studies, the present results did not show a positive correlation of BMI with the degree of steatosis, NASH and fibrosis. BMI does not always properly reflect the degree of visceral adiposity, significantly more involved in the physiopathology of NAFLD. It is possible that there is a closer correlation between the liver damage and the measure of abdominal circumference; however, this data was not evaluated in the present study, “ wrote the authors in their report.

This study showed a high prevalence of NASH in patients with MO and identified a subset of patients with a higher risk of more advanced disease, although more studies are required to confirm these data.