Serum hepcidin, the hepcidin/ferritin ratio and the risk of type 2 diabetes: A systematic review and meta-analysis

Objectives: To perform a meta-analysis on the relationship type 2 diabetes has with serum hepcidin and the hepcidin/ferritin ratio. Methods: The following databases were searched using all relevant keywords: Web of Science, Med-line, Scopus, Embase and Google Scholar. All studies that examined the relationship type 2 diabetes has with serum hepcidin or the hepcidin/ferritin ratio were included in this meta-analysis and systematic review provided, were published in English between 2011 and 2018. A random-effects model was used to pool the standardized mean difference (SMD). Results: The SMD of serum hepcidin among patients with type 2 diabetes and healthy controls were compared across eight studies (n_cases=878; n_controls=2306). The pooled SMD of serum hepcidin did not differ significantly between study groups (SMD: 0.04; 95% confidence interval (CI):-0.29 to 0.35). In contrast, the serum hepcidin/ferritin ratio was examined across five studies (n_cases=229; n_controls=1426) and was found to be negatively associated with the risk of type 2 diabetes (SMD:-0.52; 95% confidence interval (CI):-0.85 to-0.19). There was no publication bias found for the associations serum hepcidin (Egger´s test: P =0.97) or the hepcidin/ferritin ratio (Egger´s test: P =0.75) had with type 2 diabetes. Conclusion: Although hepcidin has been proposed as a risk marker for type 2 diabetes, our meta-analysis found that the hepcidin/ferritin ratio was superior to hepcidin alone as a risk marker.