Annual Healthcare Resource Utilization and Costs in US Patients Diagnosed with Relapsed Acute Myeloid Leukemia

Introduction: Acute myeloid leukemia (AML) is a malignant form of bone marrow cancer commonly diagnosed in older adults. The age-adjusted incidence of AML in the USA is 4.3 per 100,000, with a median age of 68 years at diagnosis. Once diagnosed, treatment options include intensive chemotherapy to induce remission followed by post-remission therapies, including stem cell transplantation, repeated rounds of intensive chemotherapy to achieve durable disease control, or supportive care. Prognosis following relapse is poor with a median survival of 8-10 months. While previous studies have shown that much of this time following relapse is spent in an inpatient or outpatient setting, few studies have looked at the frequency and costs of this healthcare utilization. This study examined annual healthcare resource utilization and associated costs incurred in patients diagnosed with relapsed AML.

Methods: A retrospective analysis was conducted in the Premier Healthcare Database, a nationally representative, all-payer hospital administrative database containing more than 1 billion inpatient and hospital-based outpatient encounters. Using International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) codes for AML in relapse, the study identified adult patients during the period from January 1, 2016 to March 31, 2019. The date of the first encounter with a relapse diagnosis served as the index date. Patients were followed from index date to inpatient death, one year post-relapse, or end of study period (September 30, 2019). Unadjusted descriptive analyses were performed to describe patient demographics, hospital characteristics, and comorbid conditions, as well as outcomes of interest, including outpatient treatment days, inpatient and intensive care unit (ICU) admissions, and associated costs.

Results: A total of 2,290 patients were identified for inclusion in the study. Mean age was 61.2 years (median 65.0 years) and 46.9% were female. Healthcare coverage was Medicare (51.2%), commercial insurance (29.1%), Medicaid (13.8%), or other (5.9%). Mean Charlson Comorbidity Index was 4.02 (SD 2.66) and common comorbidities were diabetes (31.0%), congestive heart failure (19.5%), and chronic obstructive pulmonary disease (19.0%). Patients' length of follow-up varied: < 90 days (49.4%), ≥ 180 days (32.8%), and ≥ 360 days (16.8%).

During the 1-year follow-up period, patients were seen in the outpatient hospital treatment setting for a median of 7.0 (IQR 2-19) days. In addition to outpatient treatment, patients incurred a total of 1,798 inpatient hospitalizations (median 2.0 per patient, IQR 1-3), with a median length of stay (LOS) of 10.0 (IQR 6-19) days. Among hospitalized patients, 554 (30.8%) included an ICU admission with a median LOS of 3.0 (IQR 1-5) days per admission.

Median cost per day for outpatient treatment was $1,039 (IQR $487-2,305) and patients incurred a median cost of $6,569 (IQR $1,872-23,542) in this setting. For hospitalizations, median cost of an inpatient stay was $21,592 (IQR $9,852-45,000). Cost of an ICU admission during a hospital stay was $13,348 (IQR $6,115-28,266). Hospital treatment costs incurred by this cohort of patients in the year following relapse totaled $169 million, of which 82% ($139 million) was attributable to the inpatient setting.

Conclusions: After a relapse of AML, patients are commonly admitted to the hospital, oftentimes to the ICU, and incur substantial costs associated with treatment. These results suggest that cost savings could be realized with therapies that would forestall relapse and improve survival in patients with AML.