Spirometric Changes After Initiation of Hydroxyurea in Children With Sickle Cell Anemia

Individuals with sickle cell disease (SCD) develop a decline in lung function over time. Hydroxyurea (HU) is the most common disease-modifying therapy used in SCD. We hypothesized that children with SCD treated with HU will have a slower decline in pulmonary function. We performed a retrospective chart review of children with HbSS and HbS-beta zero thalassemia referred to pulmonology for respiratory symptoms. We compared the spirometry results at 2 time points between children on HU (HU group) and not on HU (control group). For the HU group, these endpoints were evaluated before and after being on HU. The mean time interval between 2 spirometry studies was not significantly different between the groups (2.6 +/- 1.5 y for HU group vs. 3.0 +/- 1.8 y for the control group; P=0.33). The mean age of patients in the HU group was 9.8 +/- 3.8 years (55% male) and 10.7 +/- 4.9 years (50% male) in the control group. The spirometry data was compared within and between the groups using t test. There was a significant increase in forced vital capacity in HU group during follow-up, while children in the control group showed a decline (7.2 +/- 17.1 vs. -3.4 +/- 18.2; P <0.01). Our study suggests that HU therapy may help preserve lung function over time in children with SCD.