Trends in Acute Myeloid Leukemia (AML) Hospitalization: Incidence, Mortality, Length of Stay, and Financial Burden from 2011 to 2018

Introduction

Acute Myeloid Leukemia (AML) necessitates intensive inpatient care, including induction chemotherapy, stem cell transplantation, and management of treatment-related complications. Despite advancements in treatment, comprehensive data on hospital resource utilization and outcomes for AML patients remain limited. This study analyzes trends in the number of AML hospitalizations, in-hospital mortality, length of hospital stay (LOS), and financial burden associated with AML hospitalizations in the United States from 2011 to 2018, adjusting for inflation to provide accurate assessment.

Methods

We extracted data from the National Inpatient Sample (NIS) database - a representative sample of all hospital discharges in the United States. We included patients aged 18 years and older with a primary diagnosis of AML from 2011 to 2018. The ICD-9-CM diagnosis code 205.00 was used to identify AML hospitalizations in the 2011-2015 database. On October 1, 2015, the ICD-9 code sets were replaced by ICD-10 codes. So, we used ICD-10-CM diagnosis code C92.00 for identifying AML hospitalizations from October 1, 2015 onwards. To ensure national representativeness, we incorporated complex survey design. We conducted analyses to calculate weighted annual counts of AML hospitalizations, in-hospital mortality rates, mean LOS, and total hospital charges. Hospital charges were adjusted to 2023 dollars using the Consumer Price Index (CPI) for medical care. Statistical analyses included descriptive statistics and trend analysis using linear regression models. Design-based F-tests assessed the significance of trends over time. Our analyses applied the HCUP-NIS weights, and statistical significance was set at a p-value of < 0.01. Statistical tests were performed using STATA IC software.

Results

We identified 115,021 AML hospitalizations from 2011 to 2018. The mean age of patients was 57.59 years, with most patients aged over 70 years (31.4%), followed by 61-70 years (17.7%) and 51-60 years (15.6%). The least represented age groups were 41-50 years (10.1%) and 31-40 years (11.2%). Gender distribution showed more females (58.5%) than males (41.4%). Most patients were white (68.0%) followed by black (15.0%), hispanic (10.8%), and asian/pacific islander (2.6%). Native Americans and other races were the least represented, at 0.62% and 3.0%, respectively. Hospital disposition data showed 64.9% were discharged home whereas 16.2% were discharged to a rehab facility and 13.3% received home health care.

The in-hospital mortality rate among AML patients declined from 15.9% in 2011 to 10.3% in 2018 (p<0.01), with the lowest mortality in 2017 at 6.6%. The mean LOS for AML patients peaked at 18.1 days in 2015 and decreased to 16.6 days in 2018. It slightly increased with increasing age (0.0014 days with each year older, p<0.01) and was shorter in woman than in men (0.085 less days, p<0.01). The financial burden of AML hospitalizations, adjusted for inflation, increased significantly. Mean total hospital charges, when adjusted to 2023 dollars, rose from approximately $180,000 in 2011 to approximately $255,000 in 2018 (p<0.01). These charges were consistently lower for women, by an average of $7,001.8 (p<0.01), and increased by $106.2 with each additional year of age.

Conclusion

This study reveals decreasing in-hospital mortality rates and shorter hospital stays among admitted AML patients from 2011 to 2018 suggestive of potential advancement in the treatment and supportive care. However, the rising financial burden highlights ongoing challenges in AML management. Overall, these findings indicate a positive progression in the treatment landscape improving both in-hospital mortality and length of stay. Nonetheless, overall mortality should be correlated with outpatient data, as many patients are managed in infusion clinics after first cycle if they have shown a complete response. Strategies for early discharge can be implemented if the infusion clinics can handle almost everyday follow-ups, provide supportive care when needed, facilitate urgent hospitalizations for complications, and arrange for recovery marrow. This may reduce hospital stays and associated costs. These results underscore the need for continued efforts to optimize AML management strategies, improve patient outcomes, and address escalating healthcare costs.