Relationship between serum hepcidin levels and cardiovascular disease in patients with maintenance hemodialysis

Association between Iron Status and Survival in Patients on Chronic Hemodialysis

The aim of this study was to evaluate survival rates according to iron status in patients undergoing maintenance hemodialysis (HD). Thus, the National HD Quality Assessment Program dataset and claims data were used for analysis (n = 42,390). The patients were divided into four groups according to their transferrin saturation rate and serum ferritin levels: Group 1 (n = 34,539, normal iron status); Group 2 (n = 4476, absolute iron deficiency); Group 3 (n = 1719, functional iron deficiency); Group 4 (n = 1656, high iron status). Using univariate and multivariable analyses, Group 1 outperformed the three other groups in terms of patient survival. Using univariate analysis, although Group 2 showed a favorable trend in patient survival rates compared with Groups 3 and 4, the statistical significance was weak. Group 3 exhibited similar patient survival rates to Group 4. Using multivariable Cox regression analysis, Group 2 had similar patient survival rates to Group 3. Subgroup analyses according to sex, diabetic status, hemoglobin level ≥ 10 g/dL, and serum albumin levels ≥ 3.5 g/dL indicated similar trends to those of the total cohort. However, subgroup analysis based on patients with a hemoglobin level < 10 g/dL or serum albumin levels < 3.5 g/dL showed a weak statistical significant difference compared with those with hemoglobin level ≥ 10 g/dL, or serum albumin levels ≥ 3.5 g/dL. In addition, the survival difference between Group 4 and other groups was greater in old patients than in young ones. Patients with a normal iron status had the highest survival rates. Patient survival rates were similar or differed only modestly among the groups with abnormal iron status. In addition, most subgroup analyses revealed similar trends to those according to the total cohort. However, subgroup analyses based on age, hemoglobin, or serum albumin levels showed different trends.

Serum Hepcidin-25 and All-Cause Mortality in Patients Undergoing Maintenance Hemodialysis

Background

Hepcidin plays an important role in iron homeostasis, inhibits intestinal iron absorption and iron release from hepatocytes and macrophages, while its clinical utility remained unclear. This study aimed to investigate the associations between hepcidin-25 and mortality in MHD patients.

Methods

This was a prospective observational cohort of 161 MHD patients, with 2-year follow-up. We investigated the relationships between the variables in our dataset, including serum hepcidin-25, demographic characteristics as well as other clinical parameters.

Results

The median value of baseline serum hepcidin-25 was 31.0 (12.1, 57.3) ng/mL; therefore, the patients were stratified into two groups (low-level hepcidin-25 group, and high-level hepcidin-25 group). The serum iron, serum ferritin, transferrin saturation (TSAT), and hsCRP were higher, pre-dialysis creatinine and albumin were lower, and the scores of health-related qualities of life were worse in the high-level hepcidin-25 group than in the low-level hepcidin-25 group. Maximal information-based nonparametric exploration analysis suggested that serum hepcidin-25 was associated with ferritin, TSAT, and all-cause mortality. The patients with hepcidin-25<31 ng/mL had better survival outcomes than those with hepcidin-25≥31 ng/mL during the 24-month follow-up (Log rank test, P = 0.0017). For per 10ng/mL increase of serum hepcidin-25, the hazard ratio (HR) for all-cause mortality was 1.225 (95% confidence interval [CI]1.085-1.382, P<0.001), which remained significant after multivariate adjustments.

Conclusion

Serum hepcidin-25 was associated with ferritin and TSAT, and could be an independent predictor for all-cause mortality in MHD patients. Further research with larger sample size and longer-term follow-up is still needed.