The effects of GLP-1 receptor agonists on visceral fat and liver ectopic fat in an adult population with or without diabetes and nonalcoholic fatty liver disease: A systematic review and meta-analysis

AIM: To uncover the effect of GLP-1 receptor agonists (GLP-1 RAs) on the visceral- and hepatic fat content of adults. METHODS: PubMed, EMBASE, Cochrane Library, and Web of Science were searched from inception until November 2022. Randomized controlled trials (RCTs) of GLP-1Ras was extracted, including reports of effects on visceral adipose tissue and hepatic fat content in individuals with type 2 diabetes, non-type 2 diabetes, NAFLD (non-alcoholic fatty liver disease), and non-NAFLD. Meta-analyses used random-effects models. RESULTS: 1736 individuals in the 30 qualified RCTs were included, comprising 1363 people with type 2 diabetes and 318 with NFLD. GLP-1 RAs reduced visceral adipose tissue (standard mean difference SMD = -0.59, 95% CI -0.83, -0.36, P<0.00001) and hepatic fat content (weighted mean difference WMD = -3.09, 95% CI -4.16, -2.02, P<0.00001) compared to other control treatment. Subgroup analysis showed that GLP-1Ras dramatically decreased visceral fat in patients with type 2 diabetes (SMD = -0.49, 95% CI -0.69, -0.29 P<0.00001), NAFLD (SMD = -0.99, 95% CI -1.64, -0.34 P = 0.003), non-type 2 diabetes (SMD = -1.38, 95% CI -2.44, -0.32 P = 0.01), and non-NAFLD (SMD = -0.53, 95% CI -0.78, -0.28 P<0.0001). GLP-1Ras reduced the liver fat level of type 2 diabetes (WMD = -3.15, 95% CI -4.14, -2.15 P<0.00001), NAFLD (WMD = -3.83, 95% CI -6.30, -1.37 P = 0.002), and type 2 diabetes with NAFLD (WMD = -4.27, 95% CI -6.80, -1.74 P = 0.0009), while showed no impact on the hepatic fat content in non-Type 2 diabetes (WMD = -12.48, 95% CI -45.19, 20.24 P = 0.45). CONCLUSIONS: LP-1 RAs significantly reduce visceral- and liver fat content in adults.