Pneumonia's impact on hospitalized Acute Myeloid Leukemia patient outcomes: A national inpatient sample study (Q4 2015 – 2022)

Abstract Introduction Acute Myeloid Leukemia (AML), a crowding disease of the bone marrow, is associated with multiple in-hospital infections. Such infections are the reason behind morbidity and mortality in the majority of such patients. Pneumonia, especially in patients with advanced disease or undergoing intensive chemotherapy, plays a major role and although being of such paramount importance, a population level data showing the trends of its association with in-hospital complications and outcomes is limited. Methods We performed a retrospective analysis on 160,690 in-hospital AML patients using the NIS database (NIS Q4 2015-2021). Patients were further stratified on ICD-10-CM pneumonia codes. Our study includes a comparative analysis involving mortality, in-hospital complications, length of stay (LOS), and total hospitalization charges in AML patients with and without pneumonia. Multivariable logistic and linear regression evaluated trends in demographics, complications, and outcomes. A significance value of p<0.05 was set. All analysis was performed using Stata v17.0. Results Out of 160,690 AML patients, 30,275 (18%) had pneumonia. AML patients with pneumonia were generally older (62.85 vs 59.2; p<0.001). Male had a dominant share in patients with and without pneumonia in comparison to females (p<0.001). A higher in-hospital complications burden was found in patients with pneumonia: Acute Kidney Injury (42% vs 24%), Neutropenia (32% vs 27%), Malnutrition (27% vs 16%), Acute Cardiac Failure (8% vs 3%), Atrial Fibrillation (8% vs 6%), Stroke (4% vs 2%), Edema (6% vs 4%), Bleeding Disorders (13% vs 6%), Tumor Lysis Syndrome (13% vs 8%), UTI (8% vs 6%) and Viral Infections (9% vs 5%) with a p-value of <0.001. Pneumonia was associated with more than 2 fold increase in in-hospital mortality (22% vs 9%; aOR: 2.65; 95% CI: 2.43–2.90; p<0.001), significant increase in the LOS (25 days vs 17 days; Adjusted Coefficient Difference: +8.10 days; 95% CI: 7.31–8.89; p<0.001), total hospital charges ($391,028 vs $255,832; Adjusted Coefficient Difference: +$152,773; 95% CI: $133,483–$172,063; p<0.001). Patients with pneumonia recorded less routine discharges (38% vs 52%) than the patient group without Pneumonia (p<0.001). Conclusion In this nationwide cohort of AML inpatients, those with concurrent pneumonia experienced significantly worse outcomes than those without. Higher mortality rates, longer hospital stays, higher hospitalization cost, and fewer routine discharges are all linked to such patients. Moreover, they are also linked to higher rates of kidney injury, neutropenia, cardiac events, and more. These findings necessitate a critical need of routine screening and timely exhaustive management of different factors associated with mortality in an AML patient with concurrent pneumonia.