“Long-term observational studies suggest beneficial effects without excessive damage to bone
marrow, deleterious effects on growth and development, altered fertility, accumulation of
mutations or increased carcinogenicity,” said Dr. McLaren.
“Evidence that lung function may be better preserved while on hydroxyurea may encourage
compliance and adherence to this medication for patients with sickle cell disease,” added Dr.
McLaren. “In combination with the established safety data, it hopefully will promote physician
recommendations for hydroxyurea initiation and encouragement of compliance.”
Contact for study: A. McLaren, MD, anya.mclaren@sickkids.ca
###
Abstract 6146
Effect of Hydroxyurea on Pulmonary Function Decline in Children with Sickle Cell Disease
A. McLaren
1
, M. Klingel
2
, S. Behera
3
, M. Kirby-Allen
3
, I. Odame
4
, H. Grasemann
1
1
Division of Respiratory Medicine, Hospital for Sick Children - Toronto, ON/CA,
2
Program in
Physiology and Experimental Medicine, Research Institute, Hospital for Sick Children - Toronto,
ON/CA,
3
Division of Hematology/Oncology, Hospital for Sick Children - Toronto, ON/CA,
4
Div
of Haematology/Oncology, Hospital for Sick Children - Toronto, ON/CA
Abstract Body
Introduction
Sickle cell disease (SCD) is one of the most common inherited blood disorders, affecting 1 in
600 African Americans. Pulmonary complications are the leading cause of morbidity and
mortality in adults with SCD and a low FEV1 is predictive of earlier death. Hydroxyurea (HU) is
known to decrease the number of acute sickle-related events such as pain and acute chest crises
(ACS). We hypothesize that hydroxyurea (HU) therapy prevents the expected annual decline in
pulmonary function in children with SCD.
Methods
Research Ethics Board approval was obtained for this project. Study participants were initiated
on HU as decided by the treating hematologist. Participants were followed clinically over a 4-
year period at 3, 6, 9, 12, 24, 36 and 48-month time points after HU initiation in Sickle Cell
Clinic. Laboratory measurements (complete blood count, hemoglobin F, liver and renal function
tests) were monitored at each of these time points. Pulmonary function tests (PFT) were
collected up to median of 3.68 years pre and 3.84 years post initiation of HU. Percent predicted
values were calculated using the NHANES reference equations. Linear regression analysis using
generalized estimating equations to account for repeated measures were used to assess how
outcomes differed with the use of HU after adjusting for time and other relevant covariables.