Association between hepcidin levels and inflammatory bowel disease: A systematic review and meta-analysis of observational studies

Hepcidin has a crucial role in iron homeostasis upon inflammatory conditions such as inflammatory bowel disease (IBD). Thus, we conducted a systematic review and meta-analysis to determine the overall association between serum hepcidin concentrations and IBD. Based on the preferred reporting items for systematic review and meta-analysis (PRISMA) protocols, an electronic literature search was conducted on PubMed/MEDLINE, Scopus, and Web of Science until June 2020. Studies were deemed eligible for inclusion if they met the following criteria: (1) diagnosis of IBD, (2) observational design, and (3) measured serum hepcidin and prohepcidin concentrations in IBD patients and control group. Overall, 10 studies including 1184 participants were evaluated. Random-effects meta-analysis revealed that subjects with IBD had 7.22 ng/mL (95% CI: 2.10, 12.34; p = .006) higher serum hepcidin concentrations compared to control groups. A nonsignificantly lower serum prohepcidin concentration (0.522 ng/mL, 95% CI: -1.983 to 0.939; p = .484) was found for IBD patients compared to healthy subjects. However, there was significant heterogeneity among the studies regarding both hepcidin (I2 = 98%, p < .001) and prohepcidin levels (I2 = 96%, p < .001), respectively. In an age-based subgroup analysis, patients aged >= 18 years with IBD displayed higher serum hepcidin levels when compared to healthy individuals (22.36 ng/mL, 95% CI, 2.12-42.61; p = .030). Hepcidin concentrations are elevated in subjects with IBD; however, the clinical relevance of this finding requires further evaluation in future investigations as the increase is relatively small compared to the wide range of normal hepcidin values.