The Impact of Overweight and Obesity on Mortality and Other Outcomes in Patients Admitted with Acute Myeloid Leukemia: A National Inpatient Sample Analysis
Authors: Singh Sneha , Khadka Sushmita , Jose Thulasee , Jain Hardik 
Published: December 2024

Introduction: Obesity is a chronic, multifactorial disease and a major public health concern, especially in the United States, where it affects 42% of adults. The impact of obesity on cancer is intricate, leading to increased risk and poorer prognosis in some cases, while showing an obesity paradox in others. Various studies have been performed to understand the relationship between obesity and acute myeloid leukemia (AML) with variable results. This study is aimed to investigate the association between body mass index (BMI) and mortality, and resource utilization in AML patients admitted to hospitals across the United States.

Methods: This is a nationwide retrospective cohort study of adult patients hospitalized with AML as the primary diagnosis at acute care hospitals across the United States in 2021, using the National Inpatient Sample (NIS) database. International Classification of Diseases, 10th Revision (ICD-10) codes were utilized to identify patients with a primary diagnosis of AML and a primary or secondary diagnosis of overweight and obesity. The primary outcome is defined as the effect of overweight and obesity on in-hospital mortality. The secondary outcomes are length of stay (LOS) and total hospitalization charges. We performed multivariate logistic regression analysis to assess the effect of overweight and obesity on in-hospital mortality, LOS, and total hospitalization charges after adjusting for potential confounders such as age, race, Charlson comorbidity index, hospital teaching status, hospital region, and hospital size.

Results: Our study identified a total of 15,595 AML patients, with 18% of them also diagnosed with overweight and obesity. In-hospital mortality was observed in 11% of patients with AML. Increased age and higher Charleston comorbidity were observed as independent risk factors of increased odds of mortality in patients with AML. Obese and overweight patients with AML were observed to have lower in-hospital mortality compared to non-obese patients with (adjusted Odd's Ratio [aOR]: 0.69, confidence interval [CI]: 0.48-0.98, p=0.04).In addition, obese and overweight patients with AML were noted to have greater mean LOS than non-obese patients (20.1 days vs 17.12 days) and total hospitalization charges ($2,97,347.7 vs $26,0681.2) but did not reach statistical significance. Urban teaching hospital status and large hospital size were observed to be an independent predictor of increased LOS and total hospitalization charges in patients admitted with AML.

Conclusion: Our study demonstrates the obesity paradox by showing decreased odds of inpatient mortality in obese and overweight patients hospitalized for AML. Previous studies have shown no overall difference in survival between obese and non-obese patients, and the observed paradox here could be due to potential other confounding factors such as treatment modality and malnutrition. Higher mean LOS and total hospitalized charges for patients with obesity and overweight reflect the increased overall burden of these factors on healthcare utilization resources. Further studies are needed to comprehend this complex relationship to offer guidance on future intervention strategies.