Understanding the role of asthma in acute chest syndrome: a comparative analysis of patients with and without asthma

While asthma is a known risk factor for Acute Chest Syndrome (ACS) and may increase overall mortality in SCD patients, this study specifically focuses on the rate of inpatient mortality, hospital stay, and costs in SCD patients who develop ACS. Our study was conducted using a retrospective cohort from the National Inpatient Sample (NIS), spanning 5 years from 2016 to 2020. Patients were carefully divided into two cohorts for comparison: those admitted with ACS and a history of asthma and those with ACS without a history of asthma. The primary endpoint was all-cause inpatient mortality, and we built a robust multivariate regression model adjusting for confounders. We also thoroughly examined secondary endpoints, including a comparison of length of stay (LOS), hospital, transfusion rates, mechanical ventilation (MV) rates, Continuous Renal Replacement Therapy (CRRT), and rates of hemodialysis (HD) for acute kidney injury (AKI). Our analysis of LOS and total cost was conducted using a multivariate linear regression model adjusted for confounders, ensuring the thoroughness and validity of our results. Additionally, genotypes, demographics, and common comorbidities were described. Categorical variables required Chi-square (X2), and continuous variables required a Student t-test for hypothesis testing. A two-tailed P-value of < 0.05 was considered statistically significant. We utilized the National Inpatient Database (NIS). A total of 26,280 hospitalizations met the inclusion criteria:5,685 had ACS with a history of asthma, and 20,622 without ACS. Patients with ACS and Asthma were younger (mean age, 28 years vs. 32 years; p < 0.001), and females represented a higher proportion (53.03% vs. 47.56%; p = 0.940). Patients admitted with ACS and Asthma did not have higher odds of dying than those admitted with ACS without asthma (p = 0.176). The Charlson Comorbidity Index (CCI) was the only predictor of mortality. (aOR 1.52; p < 0.001). ACS with Asthma was a predictive factor for LOS (coefficient -0.65; p = 0.009). Conversely, female patients had a higher likelihood of experiencing a more extended hospital stay (coefficient, 0.61; p = 0.001). Additionally, ACS with Asthma significantly affected the total cost (coefficient: -15,201; p < 0.001), resulting in a lower cost than ACS patients without asthma. Finally, patients with ACS with Asthma did not have higher rates of transfusions, MV, CRRT, or HD due to AKI than those without asthma. Asthma did not increase the risk of in-hospital mortality in this large retrospective cohort study of patients admitted for Acute Chest Syndrome (ACS). While patients with ACS and a history of asthma were younger and had a lower total cost of care, their length of stay was shorter, and they did not experience higher rates of transfusion, mechanical ventilation, or acute kidney injury requiring dialysis. The primary predictor of mortality was the Charlson Comorbidity Index (CCI), highlighting the importance of overall comorbidity burden. These findings suggest that although asthma is a known risk factor for ACS, it does not independently worsen patient outcomes or survival, underscoring the need for a broader focus on managing comorbid conditions in these patients.