INTRODUCTION: Obstructive sleep apnea (OSA) was reported to be highly prevalent in children with Sickle cell disease (SCD). However as most of the published studies on SCD and OSA were patients with African ethnicity, it is not clear if it was secondary to the African race or directly to the disease itself. The aim of this study is to compare the polysomnographic features between Arab-Indian and Benin (central african)  phenotypes of SCD.

METHODS: This was a prospective cross-sectional study conducted between January 2016 and March 2020 in the Children?s Hospital at KFMC, Saudi Arabia. Children were recruited from a pediatric hematology clinics. Baseline data including clinical and demographic information, and sleep questionnaires were collected at the time of recruitment and Polysomnography (PSG) studies were performed.

RESULTS: 84 children (37 of whom were females) with SCD were included in the study. Their median (interquartile) age was 9 (6.65, 11) years and their body mass index z-score was -1.45 (-2.195, -1.45). The evidence of OSA was more prominent in the Benin phenotype (66.7%) in comparison to those of the Arab-Indian (35.2%) phenotype (p=0.006). Additionally, 56.7% of Benin had moderate to severe OSA whereas Arab-Indian had 18% with a (p=0.0003). Controlling for other factors(age, gender, BMI, SCD genotype, Hb level and Hydroxyurea use) , odds ratio (confidence interval) of having OSA in Benin phenotype was 4.68 (1.42- 15.38) times higher as compared to Arab-Indian phenotype.

CONCLUSION: The risk of having OSA and the severity of OSA is higher in Benin phenotype when compared to the Arab-Indian phenotype which indicate the presence of potential OSA risk factors other than the SCD itself.