Roux-en-Y gastric bypass (RYGB) results in a greater reduction in markers for hepatocellular injury and similar weight loss in patients with nonalcoholic steatohepatitis (NASH), compared to patients with simple nonalcoholic fatty liver (NAFL), according to researchers from Geneva University Hospitals, Switzerland. The findings were reported in the paper, ‘Impact of Nonalcoholic Steatohepatitis on the Outcome of Patients Undergoing Roux-en-Y Gastric Bypass Surgery: a Propensity Score–Matched Analysis’, published in Obesity Surgery.
The authors write that it is currently unknown whether NASH, as compared to NAFL, is associated with impaired postoperative weight loss and metabolic outcomes after RYGB surgery. Therefore, they decided to compare the effectiveness of RYGB on patients with NASH versus those with simple nonalcoholic fatty liver (NAFL).
They retrospectively data on all patients undergoing RYGB with a concomitant liver biopsy between January 1997 and December 2013. Patients were divided in two groups - 421 patients with simple NAFL and 94 with NASH, with clinical and biochemical outcomes collected at baseline (before surgery) and at the 12-month follow-up visit.
At baseline, the majority of the patients in the NASH group were male, had higher glycaemia, Homa-IR values, and levels of aminotransferases in the blood, and presented a more severe grade of liver steatosis. There was also a higher prevalence of T2DM and hypertension in the NASH group.
At 12 months, patients in the NASH group experienced a significantly greater reduction in ALT (p<0.001), AST (p<0.001), glycemia (p<0.001), fasting insulinemia (p=0.014) and Homa-IR (p=0.001). However, the NASH group still had a higher proportion of patients with T2DM vs. NAFL group (9% vs. 1.5%, p=0.001). Patients in the NASH group had a less marked EWL vs the patients in the NAFL group (71.9% vs. 77.3%, p=0.012). Median BMI change at 12 months was comparable in both groups (-14.9 vs -14.6, p=0.448).
After performing a MANOVA test (adjusted for patient age, gender, baseline BMI, presence of type II diabetes and ASA score), the researchers reported that patients with NASH experienced a significantly greater adjusted decrease in ALT (p=0.021), insulinemia (p=0.001) and Homa-IR (p<0.001). In contrast, the adjusted impact of NASH on the reduction in AST (p=0.619) and on EWL (p=0.244) was no longer significant.
Propensity scoring resulted in patients in the NASH group having a significant reduction of ALT levels in the blood vs the NAFL group (p=0.003). Both groups experienced similar EWL and change in BMI. There was also a significant difference in terms of change in AST between the groups (p=0.007).
“In summary, the current study compares for the first time the outcomes of patients with NASH versus those with simple steatosis after RYGB surgery,” the authors concluded. “Our results indicate that patients with NASH are appropriate candidates for this surgical procedure, as evidenced by a more profound reduction in markers of hepatocellular injury with similar excess weight loss, as compared to obese counterparts with simple steatosis.”
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