Early Initiation of Inhaled Corticosteroids Does Not Decrease Acute Chest Syndrome Morbidity in Pediatric Patients with Sickle Cell Disease
Authors: Leonard Alexis , Godiwala Nihal , McCarter Robert , Sharron Matthew , Meier Emily Riehm 
Published: October 2019

Abstract
Acute chest syndrome (ACS) is the leading cause of mortality in patients with sickle cell disease (SCD). Because the etiology of ACS is multifactorial, treatment approaches include broad spectrum antibiotics, intravenous fluids to prevent sickling, encouragement of ambulation, and incentive spirometry. Inflammation, airway hyper-reactivity, and ventilation/perfusion mismatch are also important in ACS etiology, but inhaled corticosteroids (ICS) are not universally initiated and efficacy still needs to be demonstrated in the treatment of ACS. Systemic corticosteroids have previously been investigated as part of the treatment for ACS. In these studies, patients who received systemic steroids had shorter hospital stays, but they were more likely to be readmitted with sickle cell painful vaso-occlusive crises (VOC). ICS may be a safe alternative to systemic steroids in patients with ACS. The current study aims to investigate the utility of initiating ICS at the time of hospital admission in reducing ACS morbidity (defined here as transfer to the pediatric intensive care unit (PICU), the need for BiPAP, intubation or pRBC transfusion) or hospital costs in SCD patients who were admitted to the hospital with VOC or ACS.
A case control study was initiated to compare patients with a discharge diagnosis of ACS at a large, tertiary care children's hospital. Cases were those patients in whom ICS were initiated at the time of hospital admission for VOC or ACS. Controls were patients who did not receive ICS upon hospital admission. Outcome measures included rate of PICU transfer, transfusion requirements, need for intubation or BiPAP initiation, and hospital cost. Student t-tests were used to compare continuous variables between the cases and controls and Pearson chi-squared was used to compare categorical variables.
A total of 120 patients with SCD admitted for ACS or VOC who later developed ACS were analyzed (55 controls vs. 65 cases). Eighty-one percent of the cases had HbSS, compared to 67% of the controls (p=0.07). Cases and controls were age matched (9.9±6.2 yrs vs. 8.7±5.5 yrs, respectively, p=0.28). A higher proportion of the cases had asthma (52.3% vs. 12.7%, p<0.001) and were followed in Pulmonology clinic (33.9% vs. 7.3%, p=0.001). Mean admission hemoglobin (Hb) and absolute reticulocyte counts (ARC) did not differ between the two groups (Case mean Hb 7.9±1.4 g/dL vs. Control mean Hb 8.5±1.8g/dL, p=0.05; Case mean ARC 308±155 K/µL vs. Control mean ARC 277±170K/µL, p=0.32). No statistically significant difference was seen in the proportion of cases who received pRBC transfusions when compared to the controls (56.9% vs. 41.8%, respectively, p=0.10). Twenty-one patients in the study cohort were transferred to the PICU [12 cases (18.5%) and 9 controls (16.3%), p=0.80]. Of those twenty-one patients who were transferred to the PICU, a lower proportion of cases required intubation (8.3% vs. 33.3% of controls, p=0.15), but more patients who began ICS at admission required BiPAP (15.3% vs. 5.4%, p=0.02). Hospital costs were slightly higher in the cases ($10,400 vs. $10,300 for the controls, p=0.40).
Initiation of ICS in this case control study did not significantly decrease the rate of ACS morbidity. Patients who received ICS at admission were more likely to have HbSS and asthma, suggesting that the cases in this study may have had more severe ACS than the controls. This could explain why a higher proportion of the cases required PICU transfer and BiPAP initiation despite receiving ICS. Despite a plausible pathogenic mechanism for the use of ICS to reduce airway hyper-reactivity, we did not see a statistically significant benefit in the treatment of ACS. Prospective studies of the use of ICS to prevent ACS or decrease its morbidity are needed.

Disclosures
No relevant conflicts of interest to declare.