Hydroxyurea (HU) is used as a disease-modifying agent in sickle cell disease (SCD). Its beneficial effects have been ascribed to inhibition of the sickling process through increase of fetal hemoglobin (HbF) levels and influence on multiple factors affecting adhesion of erythrocytes to vascular endothelium. The present study investigates the effect of HU in SCD patients who were grouped on the basis of association with α- and β-thalassemia using routine laboratory methods. A retrospective cross-sectional chart-review was done of 51 adult Bahraini SCD patients attending Salmaniya Medical Complex, Bahrain. Four sub-groups of cases were identified: (i) homozygous sickle cell anemia, 24 cases; (ii) SCD with microcytosis, 16 cases; (iii) sickle α-thalassemia, seven cases; and (iv) sickle β thalassemia, four cases. Documented laboratory and clinical data included hemoglobin level (Hb), hematocrit (Hct), red cell indices, hemoglobin fractions, hospital admissions (frequency), number of inpatient-days, pain episodes (frequency) and red cell transfusion requirement (number of units). Pre- and post-treatment data were compared. Hydroxyurea treatment led to highly significant reduction of HbS % and pain crisis episodes in all patient groups. Other changes such as increases of total hemoglobin, Hct and HbF and reduction of hospital admissions, inpatient days and red cell units transfused also occurred but with less consistent levels of significance within patient sub-groups. Treatment with HU is beneficial for all subgroups of Bahraini SCD patients, without or with α- and β-thalassemia interactions.
Keywords: Fetal hemoglobin; Hydroxyurea; Sickle cell disease; Thalassemia.