# Impact of red blood cell distribution width on response to HIF-PH inhibitor in improving anemia and clinical outcomes in patients with chronic kidney disease

## TL;DR

This study shows that red blood cell distribution width (RDW) can predict how well patients with kidney disease will respond to a new anemia treatment.

## Contribution

The study identifies RDW as a novel predictor of HIF-PH inhibitor efficacy in treating anemia in chronic kidney disease patients.

## Key findings

- Baseline RDW-CV independently predicted improvement in anemia after HIF-PH inhibitor treatment.
- An RDW-CV cutoff of 13.7% predicted treatment success with high specificity.
- RDW-CV was not linked to overall or kidney-related prognosis.

## Abstract

The clinical feasibility and efficacy of hypoxia-inducible factor prolyl hydroxylase (HIF-PH) inhibitors in patients with anemia in chronic kidney disease (CKD) remain uncertain. Red blood cell distribution width (RDW) may serve as a potential predictor for responsiveness to HIF-PH inhibitor therapy.

Consecutive patients receiving HIF-PH inhibitors for anemia in CKD over three months were included. The predictive value of baseline RDW for the improvement in anemia in CKD, defined by the increase in hemoglobin levels to 10.0 g/dL or higher at within the first three months after initiation of therapy and the maintenance of that level thereafter, was assessed.

A total of 106 patients were enrolled (median age 79 years; 57 males; 75 patients with heart failure; median estimated glomerular filtration rate 25.0 mL/min/1.73 m²; median hemoglobin level 9.3 g/dL). Among these, 84 patients met the primary outcome criteria. Baseline RDW-coefficient of variation (CV) ranged from 11.8% to 22.4%, with a median of 14.0%. Baseline RDW-CV independently predicted the primary outcome, with an odds ratio of 2.43 (95% confidence interval: 1.42–4.14, p < 0.01). The optimal cutoff value for predicting the primary outcome was identified as 13.7% (sensitivity 0.67, specificity 0.86). In addition, baseline RDW-CV levels were not significantly associated with overall and renal-related prognosis.

Baseline RDW-CV independently predicts the therapeutic efficacy of mid-term HIF-PH inhibitor treatment for anemia in CKD.

Not applicable.

The online version contains supplementary material available at 10.1186/s12882-025-04675-2.