P1382RED CELL DISTRIBUTION WIDTH - A POTENTIAL MARKER FOR IRON OVERLOAD DIAGNOSIS IN CHRONIC HEMODIALYSIS PATIENTS
Authors: Daniela Radulescu , Onofrei Simona-Daniela , Mihaela Madalina Brinzea , Ileana Adela Vacaroiu , DAVID CRISTIANA 
Published: June 2020

Abstract

Background and Aims
The indication for starting iron supplementation in chronic hemodialysis patients is precisely stipulated in all guidelines, while the criteria for stopping or reducing iron administration are still a subject of debate. Inflammatory status is a characteristic of chronic dialysis patients and it increases ferritin levels in this population; therefore iron overload is difficult to diagnose. The aim of this study was to investigate the relationships between red cell distribution width (RDW) and ferritin levels in stable maintenance hemodialysis patients, in order to help differentiating iron overload-induced increased ferritin from inflammation-induced causes.

Method
In a retrospective analysis, we studied the biochemical parameters in the last 9 months in 88 patients on maintenance hemodialysis (59.09% males) from 2 dialysis centers, mean age and dialysis duration 66.94 years, and 56 months respectively. Patients with active infections or history of neoplasia, hematologic diseases (other than CKD-associated anemia) or immunosuppressive use were excluded, and also patients having less than 3 months dialysis. Mean values (expressed as average value ± standard deviation) for ferritin, RDW (reference interval 10-15%) and C-reactive protein - CRP (reference interval 0-0.5 mg/dL), assessed every 3 months, were analyzed, and Spearman bivariate correlation test was applied to assess each pair of variables using IBM SPSS 20 for Windows.

Results
65 patients were qualified as eligible. Mean values of ferritin, RDW and CRP were 638.57± 530.84 ng/mL, 16.15±2.09 %, and 2.04±5.43 mg/dL respectively. We found a strong positive correlation between RDW and CRP values (p=0.002; rho=0.357; 1-tailed), but no relationship between CRP and ferritin (p=0.273; rho=0.076) or between RDW and ferritin (p=0.329; rho=0.056) at the entire cohort of studied population.
According to RDW values, we then divided the patients into two groups: group A with high RDW (≥15%), 48 patients (73.84 %) and group B with normal RDW (10-15%), 17 patients (26.15%), and analyzed correlations between the study parameters. There was no relationship between RDW and ferritin in group A (p=0.286; rho=0.075), and neither between RDW and CRP (p=0.092; rho=0.174). In group B, there was a highly significant correlation between RDW and ferritin levels (p=0.018; rho=0.414), and also between RDW and CRP levels (p=0.037; rho=0.357), pointing out an inflammatory state.

Conclusion
Elevated levels of RDW are usually associated with iron deficiency, and in dialysis population also with increased CRP as inflammatory marker.
We found in the present study that the RDW values used in conjunction with ferritin level may be useful in differentiating between inflammation-caused increased ferritin levels and iron-overload-caused increased ferritin levels. The inflammatory state is a common finding in chronic dialysis patients and it often produces increases in ferritin levels, making RDW a handy and helpful marker in monthly iron prescriptions, additional to CRP.