Bariatric surgery affects plasma levels of alanine aminotransferase independent of weight loss: A registry-based study

Shira Azulai, Ronit Grinbaum, Nahum Beglaibter, Shai Meron Eldar, Moshe Rubin, Shai Carmi, Rachel Ben-Haroush Schyr, Orly Romano-Zelekha, Danny Ben-Zvi*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


Patients that undergo bariatric surgery experience weight loss and a reduction in the plasma levels of the hepatic enzymes alanine aminotransferase (ALT) and aspartate aminotransferase (AST). We used the Israeli national bariatric registry, which includes demographic, clinical, and biochemical data on 19,403 patients, of which 1335 patients had two-year follow-up data on ALT, AST, A1C, and BMI, to test the dependence of the reduction in the levels of ALT and AST on weight loss. The data were analyzed using regression models, retrospective matching, and time course analyses. Changes in liver enzymes did not correlate with change in BMI, and linear regression models did not demonstrate that the change in ALT and AST values were dependent on pre-operative levels of BMI or the extent of weight loss. ALT and AST levels were reduced two years after surgery compared with a cohort of retrospectively matched patients for ethnicity, sex, age, BMI, and A1C. Finally, patients who regained weight displayed a reduction in levels of liver enzymes. Our results suggest that bariatric surgery affects AST and ALT levels via weight loss dependent and independent mechanisms. Mechanistic studies that will identify the nature of this effect and the clinical relevance of ALT and AST levels to the post-bariatric liver function are warranted.

Original languageAmerican English
Article number2724
JournalJournal of Clinical Medicine
Issue number12
StatePublished - 20 Jun 2021

Bibliographical note

Publisher Copyright:
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.


  • A1C
  • ALT
  • AST
  • Bariatric surgery
  • OAGB
  • Obesity
  • RYGB
  • Registry
  • Sleeve gastrectomy


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