Efficacy and Safety of Hydroxyurea in the Treatment of Sickle Cell Anemia Children in Jos, North Central Nigeria

Introduction: Sickle Cell Anaemia (SCA) is a genetic disorder with significant morbidity and mortality, and Nigeria accounts for the highest burden of the disease worldwide. Hydroxyurea has been shown to positively modify the disease pathogenesis, but its use is low among Nigerian SCA patients because of efficacy and safety concerns. Hence, this study evaluated the efficacy, tolerability and safety of hydroxyurea in Nigerian children with SCA.

Methods: A Quasi-experimental study with a before and after design using hydroxyurea as the intervention in 54 SCA children aged 4-17years, who have had at least two or more painful vaso-occlusive events requiring parenteral analgesia in the previous 12 months.

The number of Vaso-Occlusive Crisis (VOC), Acute Chest Syndrome (ACS), blood transfusions and hospitalisations in the previous 12 months obtained from the subjects' hospital records; and percentage fetal haemoglobin, Packed Cell Volume (PCV), White Blood Cell Counts (WBC) and Platelet Counts at baseline and after 12 months of hydroxyurea therapy were compared.The research participants were observed clinically for tolerability and adverse events of hydroxyurea while haematologic toxicity of hydroxyurea was monitored using complete blood count at specified intervals.

Wilcoxon Signed-Rank Test was used to compare the differences in the median values of the clinical and haematologic parameters at baseline and after 12 months of hydroxyurea therapy and a p-value of < 0.05 was considered statistically significant.

Results: The number of VOCs and hospitalisations reduced from the median baseline values of 3(2-3) and 2(2-3) respectively to 0(0), (p <0.0001). Blood transfusions as well as ACS declined from 48.1% and 11.2% at baseline to 5.6% and 0.0% respectively (p <0.05). The median PCV increased from 26.0(22.0-27.0) % to 28.0(25.8-30.2) % (p <0.0001) while the median WBC reduced from 11.1(7.3-14.6) x 10⁹/L to 6.2(4.8-10.4) x 10⁹/L (p < 0.0001) and the median platelet counts reduced from 411(264-496) x 10⁹/L to 347(251-402) x 10⁹/L (p= 0.009). A dose-dependent and reversible leucopenia was observed among six children (11.1%), otherwise, hydroxyurea was safe and well tolerated in the study population.

Conclusion: These findings suggest that hydroxyurea is efficacious, tolerable and safe in SCA children in Jos, Nigeria. The findings could serve as part of an educational template that could help improve the level of utilisation of hydroxyurea among sickle cell anaemia children in Jos, Nigeria.