OBJECTIVE Several studies have explored the impact of nonalcoholic fatty liver disease (NAFLD) on risk of incident type 2 diabetes. However, the extent to which NAFLD may confer risk of incident diabetes remains uncertain. We performed a meta-analysis of relevant studies to quantify the magnitude of the association between NAFLD and risk of incident diabetes. RESEARCH DESIGN AND METHODS We collected data using PubMed, Scopus, and Web of Science from January 2000 to July 2017. We included only large (n ≥500) observational studies with a follow-up duration of at least 1 year in which NAFLD was diagnosed on imaging methods. Eligible studies were selected according to predefined keywords and clinical outcomes. Data from selected studies were extracted, and meta-analysis was performed using random-effects modeling. RESULTS A total of 19 observational studies with 296,439 individuals (30.1% with NAFLD) and nearly 16,000 cases of incident diabetes over a median of 5 years were included in the final analysis. Patients with NAFLD had a greater risk of incident diabetes than those without NAFLD (random-effects hazard ratio [HR] 2.22, 95% CI 1.84–2.60; I² = 79.2%). Patients with more “severe” NAFLD were also more likely to develop incident diabetes; this risk increased across the ultrasonographic scores of steatosis (n = 3 studies), but it appeared to be even greater among NAFLD patients with advanced high NAFLD fibrosis score (n = 1 study; random-effects HR 4.74, 95% CI 3.54–5.94). Sensitivity analyses did not alter these findings. Funnel plot and Egger test did not reveal significant publication bias. Study limitations included high heterogeneity, varying degrees of confounder adjustment across individual studies, and lack of studies using liver biopsy. CONCLUSIONS NAFLD is significantly associated with a twofold increased risk of incident diabetes. However, the observational design of the eligible studies does not allow for proving causality.

To assess the efficacy of glucagon-like peptide-1 receptor agonists (GLP-1 RAs) for treatment of nonalcoholic fatty liver disease (NAFLD) or steatohepatitis (NASH), we performed a systematic review and meta-analysis of randomized controlled trials (RCTs). Three large electronic databases were systematically searched (up to 15 December 2020) to identify placebo-controlled or active-controlled RCTs using different GLP-1 RAs. We included eleven placebo-controlled or active-controlled phase-2 RCTs (involving a total of 936 middle-aged individuals) that used liraglutide (n = 6 RCTs), exenatide (n = 3 RCTs), dulaglutide (n = 1 RCT) or semaglutide (n = 1 RCT) to specifically treat NAFLD or NASH, detected by liver biopsy (n = 2 RCTs) or imaging techniques (n = 9 RCTs). Compared to placebo or reference therapy, treatment with GLP-1 RAs for a median of 26 weeks was associated with significant reductions in the absolute percentage of liver fat content on magnetic resonance-based techniques (pooled weighted mean difference: −3.92%, 95% confidence intervals (CI) −6.27% to −1.56%) and serum liver enzyme levels, as well as with greater histological resolution of NASH without worsening of liver fibrosis (pooled random-effects odds ratio 4.06, 95% CI 2.52–6.55; for liraglutide and semaglutide only). In conclusion, treatment with GLP-1 RAs (mostly liraglutide and semaglutide) is a promising treatment option for NAFLD or NASH that warrants further investigation.