Effect of Hydroxyurea Therapy on Growth Parameters in Older Children (6-15 Year-Old) with Sickle Cell Disease: Low Dose Versus High Dose

Growth impairment is a known complication of sickle cell disease (SCD). Few studies explored the potential effects of hydroxyurea (HU) on growth in children with SCD in relation to HU dose and response. This is a prospective study conducted at Sultan Qaboos University Hospital, Oman, and included 91 SCD patients with age below 16 years when started on HU, aiming to explore the potential effect/s of HU on growth parameters of older children with SCD in relation to their clinical improvement and the dose required for this improvement. Weight, height, and body mass index (BMI) were collected at baseline, 6 and 18 months after initiation. Anthropometric data were compared to WHO standards. Initial height and BMI Z scores (HAZ and WAZ) were lower compared to WHO norms. HAZ and WAZ did not change significantly after 6 and 18 months on HU therapy. However, BMI Z-scores improved significantly after 6 and 18 months of follow-up (p value 0.044 and 0.028 respectively). No significant changes were observed in WAZ or HAZ among patients on low dose versus those on high dose. BMI Z score improved significantly after 18 months of low dose group (p = 0.014) but did not change in those on high dose HU. In conclusion, HU therapy did not adversely affect weight and height growth in older children with SCD. BMI Z scores improved at 18 months in patients on low dose but not in those on high dose (p = 0.014).