C65-12 Clinical and Laboratory Findings in Adults With Sickle Cell Disease Which Increase Risk for Severe Acute Chest Syndrome

Rationale Acute chest syndrome (ACS), a major cause of morbidity and mortality in patients with sickle cell disease (SCD), is an umbrella term encapsulating a spectrum of etiologies and disease severities. The SCD outcomes grading system (SCOGS) was developed to provide a framework for grading SCD-related complications. ACS severity is graded 1-5 by use of: 1) antibiotic treatment only; 2) simple transfusion and/or ≤50% fractional inspired oxygen (FiO2); 3) greater than 50% FiO2, high flow oxygen, non-invasive ventilation, and/or exchange transfusion, 4) mechanical ventilation, vasopressors and/or organ support; and 5) ACS-related mortality. Our study aimed to determine risk factors at presentation predictive of severe ACS (grade 4 or 5). Methods Adult patients with SCD hospitalized at a single institution between January 1, 2021 and September 4, 2025 were included. ACS was defined as a new infiltrate involving at least one lung segment on chest radiography with fever and/or respiratory symptoms. ACS cases were grouped by severity into mild (SCOGS Grade 1-2), moderate (SCOGS Grade 3), and severe (SCOGS Grade 4-5). Descriptive statistics (mean, SD) were calculated. One-way ANOVA was performed to compare continuous variables across ACS severity groups; a p-value < 0.05 was statistically significant. Results Of the 711 cases, 185 met ACS criteria and were included in the analysis. 48.1% of the patients were male, 89.1% were Black, and 80.5% had HbSS disease. The median age was 36.3 +/- 12.9 years. The majority, 90.3%, had prior ACS episodes, 16.2% had prior stroke, and 44.3% had prior venous thromboembolism. Mild ACS was most common, occurring in 154 (83.24%); 18 (9.73%) were moderate, and 13 (7.03%) were severe. There were 7 deaths, one of which resulted from non-small cell lung cancer (non-ACS related). On admission, the severe ACS group had the highest B-natriuretic peptide (p = 0.0011), C-reactive protein (p = 0.0418), lactate dehydrogenase (p < 0.0001), and creatinine (p < 0.0001) levels, and the lowest platelet counts (p = 0.0097), compared to those with mild or moderate ACS. There was no significant difference in the hemoglobin concentration, reticulocyte, or white blood cell count on admission amongst patients with differing ACS severity. Conclusion Our study demonstrated that patients with severe ACS have evidence of multi-organ dysfunction at the time of presentation and that, possibly, use of a severity scale can be utilized to identify those at highest need for aggressive interventions including exchange transfusion and invasive supportive therapies. This study needs to be confirmed prospectively in large multicenter cohorts.