UC Davis study of hospitalized patients with acute myeloid leukemia reveals surprising results
(SACRAMENTO, Calif.) — Patients in California hospitals were more likely to die within 60 days of being diagnosed with acute myeloid leukemia – a cancer of the blood and bone marrow – if they were unmarried, lived in a less-affluent neighborhood or lacked health insurance. The UC Davis study also found that patients treated at a National Cancer Institute (NCI)-designated cancer center were more likely to survive.
“Although sociodemographic factors are well known to be important for long-term survival for patients with chronic illness and other cancers, this is the first study to find that they also play a significant role in outcomes of hospitalized patients with acute myeloid leukemia, when presumably everyone is treated similarly,” said Gwendolyn Ho, a hematologist-oncologist at the UC Davis Comprehensive Cancer Center, researcher with the Center for Oncology Hematology Outcomes Research and Training (COHORT) and lead author of the study.
The study analyzed data from the California Cancer Registry, a comprehensive database that collects detailed sociodemographic and clinical information on all patients diagnosed with cancer in the state, and from the California Office of Statewide Health Planning and Development Patient Discharge Database, which gathers clinical information on patients from all hospitals except federal (Veterans Affairs and military) hospitals. The study cohort consisted of 6,359 patients over 15 years old hospitalized with acute myeloid leukemia between 1999 and 2012.
The study found a number of interesting trends:
Socioeconomic factors mattered. Patients who were married were about 25 percent more likely to survive than patients who were single, and those who lived in affluent neighborhoods were about 20 percent –more likely to survive than those in poor neighborhoods. Patients who were uninsured were nearly 2.5 times more likely to die than those with private insurance, although significant differences were not found among those who had Medicare or other public insurance coverage.
NCI Cancer Centers had best outcomes. Patients treated at an NCI-designated cancer center had about half the risk of dying compared to patients at all other hospital types and across all age groups.
Survival improved over the 14 years of the study period. According to Ho, although specific treatment of acute myeloid leukemia has changed little over the past several decades, management of complications and provision of supportive care have improved. Reduction in early death rates occurred across all age groups, but death rates were higher with increasing age throughout the study period.
Early death was associated with complications. Patients who developed major bleeding, liver failure, renal failure, respiratory failure or cardiac arrest were more likely to die within 60 days of diagnosis. These complications continue to be primary drivers of survival in acute myeloid leukemia.
Ethnic differences were revealed. Certain complications were found more often in specific ethnic groups compared to others: renal failure in African-Americans, sepsis in Hispanics and respiratory failure in Asians. Overall, African-American patients had a lower risk of dying within 60 days than non-Hispanic white patients.
Presence of other diseases increased risk. Patients with at least three other medical conditions at the time of diagnosis were almost twice as likely to suffer early death as those who started out otherwise healthy.
Ho noted that the trends revealed in the study are likely applicable to other cancers and to patients throughout the country. Acute myeloid leukemia was studied as a model disease because treatment has changed so little in past decades and the initial treatment after diagnosis often requires hospitalization, making the potential impact of factors other than cancer treatment more apparent. She also commented on the uniquely valuable California Cancer Registry, which contains extensive data on nearly all cancer patients in a state with a diverse population.
The reserachers are currently investigating the impact of hospital type on early mortality rates and the characteristics of patients treated at specialty cancer centers.
“Understanding the factors that affect early mortality can help identify targets for improvement,” said Ho. “We expect that further study of the trends will lead to interventions to improve early survival of cancer.”
Other study authors are Theresa Keegan, associate professor of internal medicine and principal investigator of the study, and Brian Jonas, Qian Li, Ann Brunson, and Ted Wun, all of COHORT.
Funding for this study came from the National Institutes of Health (K12 CA138464) and its National Center for Advancing Translational Sciences (TR000002
UC Davis Comprehensive Cancer Center is the only National Cancer Institute-designated center serving the Central Valley and inland Northern California, a region of more than 6 million people. Its specialists provide compassionate, comprehensive care for more than 10,000 adults and children every year, and access to more than 150 clinical trials at any given time. Its innovative research program engages more than 280 scientists at UC Davis, Lawrence Livermore National Laboratory and Jackson Laboratory (JAX West), whose scientific partnerships advance discovery of new tools to diagnose and treat cancer. Through the Cancer Care Network, UC Davis collaborates with a number of hospitals and clinical centers throughout the Central Valley and Northern California regions to offer the latest cancer care. Its community-based outreach and education programs address disparities in cancer outcomes across diverse populations. For more information, visit cancer.ucdavis.edu.