Incretin-based therapies for the treatment of non-alcoholic fatty liver disease : a systematic review and meta-analysis

Background and Aim: Non-alcoholic fatty liver disease (NAFLD) is a leading cause of chronic liver disease in Western societies. Despite its significance, there are no well proven pharmacological treatments. Two novel classes of potential pharmacotherapies are the glucagon-like peptide-1 receptor agonists (GLP-1 RA) and dipeptidyl peptidase-4 inhibitors (DPP-4I), collectively known as incretin-based therapies. These have several metabolic and anti-inflammatory actions that may be of benefit in NAFLD. The aim of this meta-analysis was to evaluate their efficacy via a structured retrieval and pooled analysis of relevant studies. Methods: Studies were sourced from electronic databases and meeting abstracts. Main inclusion criteria were original studies investigating treatment of adults with NAFLD using GLP-1 RA/DPP-4I. Key outcomes were a change in serum alanine transaminase (ALT), as a marker of liver inflammation, and improvement in disease status measured by imaging or histology. Results: Initial searching retrieved 1357 peer-reviewed articles and abstracts. Four studies met all inclusion and exclusion criteria. There were a total of 136 participants with NAFLD and concomitant type 2 diabetes mellitus (T2DM). Meta-analysis (random-effects model) revealed a significant decrease in serum ALT following treatment (mean reduction 14.1 IU/L, 95% confidence intervals [CI] 8.3–19.8, P<0.0001). In two studies with imaging and tissue data, treatment was found to significantly reduce steatosis, inflammation, and fibrosis. Conclusion: The significant decrease in a key biochemical marker of hepatic inflammation following treatment with incretin-based therapies, as well as improvements in imaging and histology, suggests these agents may be effective options for managing NAFLD with comorbid T2DM.