Pulmonary function assessments and clinical correlates in children with sickle cell disease in Cape Town, South Africa

Abstract

Objectives: Among children with sickle cell disease (SCD) in Africa, there are varied reports on pulmonary function assessments. Restrictive pulmonary function is common in children with SCD in Africa; however, reports from Africa are few. We aimed to describe pulmonary function and its clinical correlates in children with SCD in Cape Town, South Africa. Materials and Methods: A prospective cross-sectional study was carried out over seven months from October 2018 to April 2019 in children 6–16 years with SCD. Children with hemoglobin (Hb) genotypes, homozygous for the BS globin mutation, and sickle-beta0-thalassemia Hb were included in the study. Children were excluded if they had acute complications. Medical record review clinical, laboratory, and pulmonary function assessments were done. Data were entered into Excel and exported to Stata Version 16.0 statistical software for analysis. Results: A total of 25 participants were recruited, mean (standard deviation) age of 10 ± (3.0) years. Thirteen (53%) children were under ten years and 15 (60%) were male. The median/interquartile range age at diagnosis was 1.7 [0.8–3.0] years. SCD-related complications were common. A review of the medical records showed a third of the patients (32%) had at least one previous episode of acute chest syndrome, 20 (80%) had a history of vaso-occlusive crisis, and 15 (76%) had required at least one blood transfusion. Spirometry was performed on 19 (76%) of the participants 9 (47%) had abnormal lung function. The most common spirometry abnormality was a restrictive pattern (forced vital capacity (FVC) < lower limit of normal (LLN)). No participant had a positive bronchodilator response. Older age was associated with a decrease in forced expiratory volume in the first second (FEV1) Z-score (−0.16, 95% confidence interval [CI] −0.31, −0.01; P = 0.04). Children on hydroxyurea similarly had reduced FEV1 Z-score (−1.5, 95%CI −2.88, −0.12; P = 0.04) and reduced FVC Z-score (−2.21, 95%CI −3.64, −0.79; P < 0.001). Conclusion: Lung function abnormalities were common among children with SCD, with restrictive abnormality predominating. Asthma and obstructive airway abnormalities were uncommon in children with SCD in South Africa.