Abstract
BACKGROUND & AIMS: Uncontrolled studies show sitagliptin, an oral DPP-4 inhibitor, may improve alanine aminotransferase and liver histology in non-alcoholic fatty liver disease (NAFLD) patients. We aimed to compare sitagliptin vs. the efficacy of a placebo in reducing liver fat measured by MRI-derived proton density-fat fraction (MRI-PDFF). METHODS: This randomized, double-blind, allocation-concealed, placebo-controlled trial included 50 NAFLD patients with prediabetes or early diabetes randomized to sitagliptin orally 100mg/day or placebo for 24weeks. Primary outcome was liver fat change measured by MRI-PDFF in colocalized regions of interest within each of nine liver segments. Additional advanced assessments included MR spectroscopy (MRS) for internal validation of MRI-PDFF's accuracy, and magnetic resonance elastography (MRE) and FIBROSpect® II to assess liver fibrosis. RESULTS: Sitagliptin was not significantly better than placebo in reducing liver fat measured by MRI-PDFF (mean difference between sitagliptin and placebo arms: -1.3%, p=0.4). Compared to baseline, there were no significant differences in end-of-treatment MRI-PDFF for sitagliptin (18.1% to 16.9%, p=0.27) or placebo (16.6% to 14.0%, p=0.07). The groups had no significant differences for changes in alanine aminotransferase, aspartate aminotransferase, low-density lipoprotein, homeostatic model assessment insulin resistance, and MRE-derived liver stiffness. In both groups at baseline and post-treatment, MRI-PDFF and MRS showed robust correlation coefficients ranging from r(2)=0.96 to r(2)=0.99 (p<0.0001), demonstrating the strong internal validity of the findings. FIBROSpect® II showed no changes in the sitagliptin group but was significantly increased in the placebo group (p=0.03). CONCLUSIONS: Sitagliptin was safe but not better than placebo in reducing liver fat in prediabetic or diabetic patients with NAFLD. LAY SUMMARY: In a randomized, double-blind, placebo-controlled study, the anti-diabetic drug sitagliptin was no more effective than placebo for improving liver fat and liver fibrosis in patients with non-alcoholic fatty liver disease. This study demonstrates that non-invasive magnetic resonance imaging techniques, including magnetic resonance imaging-proton density-fat fraction and magnetic resonance elastography, can be used to assess treatment response in non-alcoholic fatty liver disease clinical trials.