Hydroxyurea decreases hospitalizations in pediatric patients with Hb SC and Hb SB+ thalassemia

Abstract

Purpose

Patients with hemoglobin SC (Hb SC) and hemoglobin SB+ (Hb SB+) thalassemia suffer from frequent hospitalizations yet strong evidence of a clinical benefit of hydroxyurea (HU) in this population is lacking. Patients with recurrent hospitalizations for pain crisis are offered HU at our institution based on small cohort data and anecdotal benefit. This study identifies outcomes from a large cohort of patients with Hb SC and SB+ thalassemia who were treated with HU for 2 years.

Materials and methods

A retrospective review was conducted of 32 patients with Hb SC and SB+ thalassemia who were treated with HU. We reviewed the number, and reasons for hospitalization in the 2 years prior to, and 2 years post-HU treatment as well as laboratory changes from baseline, over 1 year.

Results

Patients with Hb SC and SB+ thalassemia started on HU for frequent pain, had a significant reduction in hospitalizations over 2 years as compared to the 2 years prior to HU initiation (mean total hospitalizations/year: pre-HU: 1.6 vs post-HU 0.4 hospitalizations, P<0.001; mean pain hospitalizations/year: pre-HU 1.5 vs post-HU 0.3 hospitalizations, P<0.001). Patients demonstrated hematologic changes including an increase in percent fetal hemoglobin (%HbF) pre–post HU (4.5% to 7.7%, P=0.002), mean corpuscular volume (74 to 86 fL, P<0,0001), and decrease in absolute neutrophil count (5.0 to 3.2×10⁹/L, P=0.007). Patients with higher doses of HU demonstrated the greatest reduction in hospitalizations but this was unrelated to absolute neutrophil count.

Conclusion

This cohort of patients with Hb SC and SB+ thalassemia provides additional support for using HU in patients with recurrent hospitalizations for pain. A large randomized multicenter trial of HU to reduce pain admissions should be conducted to confirm these data and provide much needed evidence based recommendations for this population.

Keywords:

• sickle cell disease
• hydroxyurea
• outcomes research
• vaso-occlusive pain crisis

Acknowledgments

Research reported in this publication was supported by the National Center for Advancing Translational Sciences of the National Institutes of Health under the award number UL1TR001417. The authors would like to acknowledge the assistance of Peng Li, PhD for providing biostatistical support through the UAB CCTS consultative services. The authors would like to thank the patients and parents in this study. Finally the authors would like to thank the Sickle Cell Nurse Practitioners (Kristen Osborn, Melissa Bagwell, Heather Carlton, Susan Dobbins, and Michelle Alleman) for providing excellent care to our patients.

Author contributions

All authors contributed toward data analysis, drafting and critically revising the paper and agree to be accountable for all aspects of the work.

Disclosure

The authors have no conflicts of interest to disclose.