Association between absolute eosinophil count and outcomes in sickle cell disease

Abstract Objective: Patients with sickle cell disease (SCD) may experience vaso-occlusive episodes (VOE) requiring hospitalization. Studies have shown that treatment with hydroxyurea reduces both eosinophil degranulation and VOE frequency among those with SCD. Since eosinophil activation appears to reflect disease at the molecular level, we sought to evaluate whether absolute eosinophil count (AEC) could predict SCD severity in the clinical setting. Methods: We performed a multicenter retrospective cohort study using the Premier Healthcare Database (2022-2024). Eligible patients had an ICD-10 diagnosis code for D57.00 (“HbSS disease with crisis, unspecified”) on admission and at least 1 AEC available within 1 day of admission. Patients were classified according to Angus-defined organ dysfunction algorithms and Gagne's combined comorbidity scores; the primary outcome was length of stay (LOS). Statistics were performed in R. Results: Among 2902 patients included, mean age was 31 ± 12 years; the majority of patients were black (95%) and non-Hispanic (91%). AEC on admission was 0.19 cells x 109/L (interquartile range: 0.08-0.36). Median LOS was 4 days (interquartile range 3-7 days). No statistically significant association was found between AEC and LOS (-0.33 [95% confidence interval -1.19 - 0.53; p=0.46). Conclusion: Although AEC may reflect SCD at the molecular level, these findings do not translate to statistically significant associations between AEC and LOS in the clinical setting.