Outcomes of follicular lymphoma patients hospitalized with viral respiratory illnesses: A national population-based study.

e19066 Background: Follicular lymphoma (FL) is an indolent B cell disorder with improving OS with the evolution of new drug agents. Prior studies have shown an increase in the mortality rate of patients with FL during the COVID-19 pandemic. The specific mortality rate of patients admitted to the hospital with acute hypoxic respiratory failure secondary to COVID-19, RSV, and Influenza is not known. This study seeks to address this knowledge gap by investigating these outcomes. Methods: Retrospective cohort study using The National Inpatient Sample database (2016–2021 for RSV and Influenza, and 2020-2021 for COVID-19) of the Healthcare Cost and Utilization Project (HCUP) was used. We applied discharge weight (DISCWT) provided in the database to generate the national estimates. Pearson Chi-square test for categorical variables and Student’s t-tests/one-way ANOVA for continuous variables were applied to compare the baseline demographics and hospital characteristics between the groups. Mortality was the primary outcome while length of stay, total hospitalization charges, the use of mechanical ventilation and ECMO constituted the secondary outcomes. Multivariate linear and logistic regression models were used to adjust for confounders such as ages, tobacco use, hypertension, COPD, Ischemic heart disease, and prior CVA. Results: Among 931,289 hospitalizations for acute hypoxic acute hypoxic respiratory failure secondary to COVID-19, RSV and Influenza, 578 patients had follicular lymphoma. After adjusting for confounders, there were higher odds of in-hospital mortality in FL patients hospitalized with COVID-19 (aOR: 1.62; CI 1.29 - 2.04; p-value < 0.001), higher odds of use of mechanical ventilation (aOR: 1.34; CI 1.04-1.73; p-value 0.024), longer LOS (7.5 vs. 5.8 days, p<0.001), and higher total hospitalization charges ($93,450 vs $119,120, p 0.016). There were no statistical significant differences in outcomes for patients hospitalized for RSV and Influenza viruses. Conclusions: Patients with FL admitted for COVID-19 pneumonia experience higher rates of mortality, mechanical ventilation, and a longer hospital length of stay. These findings highlight the heightened vulnerability of immunosuppressed FL patients and underscore the critical importance of maintaining up-to-date vaccinations in this population. FL vs No-FL in Influenza (aOR, P-value, CI) FL vs No-FL in RSV (aOR, P-value, CI) FL vs No-FL in COVID-19 (aOR, P-value, CI) In-Hospital Mortality 1.45, 0.464, 0.53 - 3.96 1.67, 0.342, 0.58 - 4.78 1.62, <0.001*, 1.29 - 2.04 Mechanical ventilation 0.66, 0.40, 0.24 - 1.77 0.66, 0.487, 0.2 - 2.15 1.34, 0.024*, 1.04 - 1.73 ECMO - - 1.73, 0.224, 0.72 - 4.18 Length of Stay 1.03, 0.8, 0.83 - 1.22 1.13, 0.37, 0.85 - 1.4 1.24, <0.001*, 1.14 - 1.35 Total Hospitalization Charges 0.92, 0.57, 0.65 - 1.19 1.38, 0.178, 0.83 - 1.94 1.27, 0.016*, 1.05 - 1.5 *Statistically significant.