Impact of Insurance Status on the Day of Admission and Clinical Outcome on Acute Myeloid Leukemia (AML)Patients

Background:

In patients with acute myeloid leukemia (AML), insurance status has not been demonstrated to adversely impact outcomes. However, insurance status appears to be an independent factor in healthcare utilization. University of Oklahoma Health Sciences Center (OUHSC) is the main tertiary hospital in the State of Oklahoma treating patients with acute leukemia. We hypothesized that treatment patterns might be different between the insured and uninsured patients. We hereby attempt to analyze the association between insurance status, week day of admission and outcomes.

Methods:

We retrospectively analyzed patients from January 2000 to June 2012 diagnosed with AML over 18 years of age, who were treated at OUHSC with induction chemotherapy. Patients were divided into two groups: Group 1 included patients who were admitted on weekdays (Monday-Thursday) and group 2 included patients admitted on weekends (Friday-Sunday). Patients were also sub-classified as having private insurance, public insurance (Medicaid and Medicare) or no insurance. Primary outcomes were overall survival at follow up (OS), complete remission (CR) and Relapse. Chi-Square analysis was utilized to assess if day of admission and insurance status was related to OS, CR and Relapse. Cox Proportional hazards model was used to measure association of insurance status, day of admission and their interaction and Kaplan Meir Survival curves were used to estimate survival rates for day of admission by insurance status.

Results:

We analyzed total of 161 patients, 157 met inclusion criteria with 69 (44%) having public insurance, 58 (37%) with private insurance and 30 (19%) were uninsured. Group 1 with 94 (60%) patients was admitted on weekdays (Monday–Thursday), and group 2 with 63 (40%) patients was admitted on weekend (Friday-Sunday). The median age at diagnosis was 49 years, 63.7% male 36.3% female. 77.0% white, 10.6% African American, 6.2% Native American and 3.7% Hispanic. We found a significant interaction between insurance status and day of admission, 63% of uninsured patients being admitted on weekend (Fri-Sun) with (p-value=0.0292). When we stratified patients by insurance status there was no difference in survival outcomes for uninsured patients based on day of admission. However, for patients with insurance who were admitted on weekdays Mon-Thurs (Group 1) had a hazard ratio (HR) of death 0.487 relative to those on weekends Fri-Sun (Group 2) (p=0.0238). Median overall survival (OS) for uninsured patients in (Group 2) was 147.5 days (95% CI=79-252) as compare to insured patients in (Group 1) 252 days (95% CI=116-459) with a P value 0.0182. The proportion of patients achieving CR did not differ by day of admission (p=0.3275) and insurance type (0.5678). Relapse was not associated with day of admission (p=0.2284) or by insurance type (p=0.4057).

Conclusions:

For the patients with the diagnosis of AML who presented to our institution, there was a noticeable trend of uninsured patients being admitted over the weekend. The overall survival was lower for the uninsured patients who were admitted on the weekend as compare to the insured patients who were admitted on weekdays. This trend is both noteworthy and significant and due to its possible impact on standard of care warrants further investigation.