Effect of novel glucose lowering agents on non-alcoholic fatty liver disease: A systematic review and meta-analysis

The efficacy of novel glucose-lowering drugs in treating non-alcoholic fatty liver disease (NAFLD) in patients with and without type-2 diabetic patients (T2DM) remains unclear.To conduct a meta-analysis to evaluate the efficacy of 3 novel glucose-lowering drug classes, namely glucagon-like peptide-1 receptor agonists (GLP-1RA), sodium-glucose co-transporter 2 (SGLT2) inhibitors, and dipeptidyl-peptidase-4 (DPP4) inhibitors on hepatic parameters: Aspartate Aminotransferase (AST), Alanine Aminotransferase (ALT), Gamma-Glutamyl Transferase (GGT), Bilirubin, and FIB-4 (Fibrosis).MEDLINE was searched from inception through October 2021 for randomized placebo or active glucose-lowering drug-controlled trials. A random-effects model was used to pool the results. A p-value of less than or equal to 0.05 was considered significant. Results were presented as weighted mean differences (WMD) and corresponding 95% confidence intervals (CIs).Our pooled analysis consisted of 40 studies. A significant reduction was seen in AST with SGLT2 inhibitors (WMD = -2.31 IU/L, 95%CI: -3.16 to -1.47 IU/L, P < 0.00001) and GLP-1RA (WMD = -3.29 IU/L, 95%CI: -5.98 to -0.61 IU/L, P = 0.02). Similarly, significant reduction was seen in ALT with SGLT2 inhibitors (WMD = -5.93 IU/L, 95%CI: -7.70 to -4.16 IU/L, P < 0.00001) and GLP-1RAs (WMD = -9.92 IU/L, 95%CI: -19.89 to 0.05 IU/L, P = 0.05). In contrast, DPP-4 inhibitors showed no significant reduction in AST (WMD = -3.20 IU/L, 95%CI: -11.13 to 4.73 IU/L, P = 0.43) or ALT (WMD = -4.81 IU/L, 95%CI: -15.83 to 6.21 IU/L, P = 0.39). A significant reduction in GGT was seen with SGLT2 inhibitors (WMD = -6.49 IU/L, 95%CI: -11.09 to -1.89 IU/L, P = 0.006) and GLP-1RAs (WMD = -12.38 IU/L, 95%CI: -15.69 to -9.07 IU/L, P < 0.00001). However, significant results were not observed with DPP-4 inhibitors (WMD = -0.92 IU/L, 95%CI: -5.80 to 3.96 IU/L, P = 0.71). There was a statistically significant reduction in FIB-4 index with SGLT2 inhibitors (WMD = -0.21, 95%CI: -0.40 to -0.03, P = 0.02) and GLP-1 RA (WMD = -0.15, 95%CI: -0.29 to 0.00, P = 0.05). Lastly, SGLT2 inhibitors led to a significant change in bilirubin levels (WMD = 2.03, 95%CI: 0.76 to 3.30, P = 0.002) while the change in bilirubin was not significant with GLP-1 agonists (WMD = -0.21, 95%CI: -1.09 to 0.66, P = 0.63) and DPP-4 inhibitors (WMD = 0.14, 95%CI: -1.55 to 1.83, P = 0.87).SGLT2 inhibitors and GLP-1 agonists have a beneficial effect on hepatic parameters in patients with NAFLD. However, further research is needed to evaluate the effect of DPP-4 inhibitors on hepatic function properly.