Circulating Ferritin in Patients with Nonalcoholic Fatty Liver Disease: A Systematic Review and Meta-analysis

To synthesize data on circulating ferritin between patients with histologically confirmed nonalcoholic fatty liver disease (NAFLD) and non-NAFLD controls. A systematic literature search was conducted in PubMed, Scopus, and the Cochrane Library. Thirty-one studies comprising data on 5631 individuals (2929 biopsy-proven NAFLD patients and 2702 controls) were included in the meta-analysis. Higher circulating ferritin levels were observed in NAFLD patients than in controls [standardized mean difference (SMD) 1.14; 95% confidence interval (95% CI) 0.73–1.55], in patients with simple nonalcoholic fatty liver (NAFL) than in controls (SMD 0.57; 95% CI 0.34–0.80), in patients with nonalcoholic steatohepatitis (NASH) than in controls (SMD 0.95; 95% CI 0.69–1.22), and in NASH than in NAFL patients (SMD 0.62; 95% CI 0.25–0.99). There was moderate-to-high heterogeneity among studies in the above pairs of comparisons (I2 = 68–97%); no risk of publication bias was observed by Egger's test (P = 0.81, P = 0.72, P = 0.59, P = 0.42, respectively). The heterogeneity was reduced in the subgroup of biopsy-proven controls in all pairs of comparisons (I2 = 0–65%). The heterogeneity was also reduced after excluding studies with the Newcastle–Ottawa Scale (NOS) score