The use of hydroxyurea in sickle cell disease: A single tertiary centre experience at the National Hospital, Abuja, Nigeria

Background. Hydroxyurea (HU) has been found to be beneficial in sickle cell disease (SCD), reducing the occurrence of severe manifestations of the disease such as painful crises and blood transfusions. Although a standard of care for SCD in the developed countries of the world, limited data are available on its use in Africa.  Objectives. To review indications of the use of HU, laboratory monitoring and outcome in children with SCD.  Methods. A retrospective review of 74 patients treated with HU (15 - 30 mg/kg/day) for a minimum of 6 months. The main outcome measures were indications for use of HU, haemoglobin level (Hb), packed cell volume (PCV), white cell count (WBC), absolute neutrophil count (ANC), serum alanine aminotransferase (ALT) and creatinine. Descriptive statistics were expressed as means ±2 standard deviations. Data were compared pre and post HU therapy, using the chi-square and Student’s t -test as appropriate.  Results. The 74 patients constituted 7.26% of the SCD clinic population and were aged 2.25 - 16 years (mean (SD) 8.48 (3.67)) and were on HU therapy for 0.5 - 4.8 years (mean (SD) 1.72 (1.12)). The haemoglobin genotypes were Hb SS 72 (98.7%); Hb SC and Hb SS+F 1 (1.35%) each. Indications for HU use were abnormalities of transcranial Doppler ultrasound (TCD) 39 (52.7%), multiple vaso-occlusive crises (VOC) 18 (24.3%), strokes 14 (18.9%), as well as repeated blood transfusions 9 (12.2%) and hospital admissions 7 (9.5%). Some patients had more than one indication. There were significantly fewer TCD abnormalities, VOC, strokes, splenic sequestrations, blood transfusions and hospital admissions following use of HU. The mean Hb and PCV increased while WBC and ANC decreased. Occurrence of acute chest syndrome, priapism, serum creatinine, ALT and platelet levels were not affected.  Conclusions. Hydroxyurea therapy reduces the occurrence of severe manifestations and improves laboratory parameters in children with SCD.