Functional Liver Recovery After Bariatric Surgery--a Prospective Cohort Study with the LiMAx Test.

BACKGROUND: Bariatric surgery provides long-term weight loss and improvement of obesity-associated diseases such as nonalcoholic steatohepatitis (NASH). Histologic improvement of NASH has been reported in some studies after bariatric surgery. This study was designed to assess the liver function in obese patients as well as its recovery after bariatric surgery with a noninvasive test method.

METHODS: In a prospective cohort study from October 2011 to May 2014, morbidly obese individuals receiving bariatric surgery were investigated for functional liver recovery (n = 34). Liver function was determined by the LiMAx test (enzymatic capacity of cytochrome P450 1A2) preoperatively, 6 and 12 months postoperatively. Liver biopsy specimens were obtained from 18 participants and classified according to the nonalcoholic fatty liver disease (NAFLD) activity score (NAS).

RESULTS: The mean age of participants was 44 years, and the mean body mass index (BMI) was 52 kg/m(2). The mean percent excess BMI loss (%EBMIL) was 53 % after 6 months and 68 % after 1 year. Mean liver function capacity increased significantly from 255 μg/kg/h preoperative to 324 μg/kg/h after 6 months and 342 μg/kg/h after 12 months. A negative correlation was observed between %EBMIL and alteration of liver function capacity in the first 6 months. Finally, the median NAS showed a negative correlation with liver function capacity.

CONCLUSIONS: Bariatric surgery leads to a significant functional recovery of the liver. An initial marked weight loss may negatively influence functional liver recovery.