Persistent Increase in Serum Ferritin Levels despite Converting to Permanent Vascular Access in Pediatric Hemodialysis Patients: Pediatric Nephrology Research Consortium Study

Abstract

Our objective was to examine serum ferritin trends after conversion to permanent vascular access (PVA) among children who started hemodialysis (HD) using tunneled cuffed catheters (TCC). Retrospective chart reviews were completed on 98 subjects from 20 pediatric HD centers. Serum ferritin levels were collected at the creation of PVA and for two years thereafter. There were 11 (11%) arteriovenous grafts (AVG) and 87 (89%) arteriovenous fistulae (AVF). Their mean TCC use was 10.4 ± 17.3 months. Serum ferritin at PVA creation was elevated at 562.64 ± 492.34 ng/mL, increased to 753.84 ± 561.54 ng/mL (p = < 0.001) in the first year and remained at 759.60 ± 528.11 ng/mL in the second year (p = 0.004). The serum ferritin levels did not show a statistically significant linear association with respective serum hematocrit values. In a multiple linear regression model, there were three predictors of serum ferritin during the first year of follow-up: steroid-resistant nephrotic syndrome as primary etiology (p = 0.035), being from a center that enrolled >10 cases (p = 0.049) and baseline serum ferritin level (p = 0.017). Increasing serum ferritin after conversion to PVA is concerning. This increase is not associated with serum hematocrit trends. Future studies should investigate the correlation of serum transferrin saturation and ferritin levels in pediatric HD patients.

Keywords: arteriovenous fistula; arteriovenous graft; ferritin; hemodialysis; pediatric.

Figure 1

Adjusted model for serum ferritin. Observed estimates (right-hand graph) and model estimates (left-hand graph and bottom table) for serum ferritin (ng/mL). The model was adjusted for primary etiology, age, BMI, anatomical location of access (radial, brachial, femoral), the number of AVF submitted per study center (<5 cases, 5–10 cases, >10 cases) and HD vintage at PVA creation. Please note that TCC represents the Ferritin baseline value; AVF1 and AVF2 represent the year 1 follow-up Ferritin value and year 2 follow-up Ferritin value for the AVF group, respectively; and AVG1 and AVG2 represent the year 1 follow-up value and year 2 follow-up value of Ferritin for AVG group, respectively. CI: 95th percentile confidence interval, P: p-value.

Figure 2

Comparative graphs of ferritin vs. hematocrit at various data points during the two years of follow-up. There was no statistically significant linear association between serum ferritin and hematocrit levels at all three data points. PVA1.Ferritin demonstrated a significant linear association with ferritin at PVA creation (right, bottom graph).