Demographic Trends in Chronic Myelogenous Leukemia in Adults in the United States between 1999 and 2020

Introduction:

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm that accounts for nearly 15% of new leukemia cases each year in the United States (U.S.). CML commonly affects older adults, with a median age of 64 at diagnosis. While the 5-year survival rate of CML is greater than 70%, disparities in mortality exist among various groups in the U.S. Currently, no studies have assessed geographic and demographic trends in CML mortality within the country. We aim to analyze demographic differences and trends in CML mortality within the U.S. between 1999 to 2020.

Methods: The CDC (Centers for Disease Control) Wonder Database was utilized to access mortality data for patients with an underlying cause of death from CML (ICD-10 code C92.1) between 1999 to 2020. Age-adjusted mortality rate (AAMR) was calculated per 100,000 deaths. The AAMR was calculated by demographic variables including sex (Male, Female), race (White, African American), and adult age groups. Joinpoint regression software was used to identify temporal trends by calculating the annual percent change (APC) and average annual percent change (AAPC) for each year from 1999 to 2020. Statistical significance was set at p<0.05.

Results: Between 1999 and 2020, CML accounted for 26,329 deaths across populations in the United States. During this time, the overall AAMR for CML decreased by 50%.

Gender-specific trends indicate a decrease in mortality rate for both males and females during this time period. For females, the AAMR declined from 0.5 in 1999 to 0.2 by 2007, with an APC of -10.6% from 1999 to 2008 (p < 0.01). Males experienced a decrease in AAMR from 0.8 in 1999 to 0.4 by 2007, with an AAPC of -8.9% during this time (p < 0.01).

Racial comparisons show that African Americans had an AAMR of 0.7 in 1999, which decreased to 0.35 by 2008, with an APC of -8.5% (p < 0.01). White Americans saw a larger reduction, with the AAMR decreasing from 0.65 in 1999 to 0.3 by 2007, reflecting an APC of -10.0% (p < 0.01).

Analysis of age groups also reveal significant variations in mortality rates over time. Across all adult age groups, mortality rates from CML have decreased between 1999 and 2020. Most notably, the AAPC decreased by 6.9% for 45-54-year-olds, 5.3% for 55-64 years old, and 5.4% for 65-74-year-olds, respectively, between 1999 - 2020 (p < 0.01).

For individuals aged 45-54 years, the AAMR decreased from 0.5 in 1999 to 0.35 by 2020, with a notable decrease in APC of -21.2% from 1999 to 2004 (p < 0.05). Similarly, for the 55-64 age group, the AAMR decreased from 1.0 in 1999 to 0.4 by 2020, with an APC of -11.9% between 1999 and 2020 (p < 0.05). In the 65-74 age group, the AAMR decreased from 2.25 in 1999 to 0.8 by 2008, with a corresponding decrease in APC of -11.0% from 1999 to 2007 (p < 0.05). The 75-84 age group showed an initial increase in AAMR from 2.4 in 1999 to a peak of 3.8 in 2006, followed by a decrease to 2.25 by 2011. The APC had a notable increase of 19.5% from 2003 to 2006 (p < 0.05). This was followed by a subsequent decrease of -10.4% from 2006 to 2011 (p < 0.05). The oldest age group, 85 years and older, had an AAMR of 5.25 in 1999, which decreased to an AAMR of 4.7 by 2020, still notably elevated compared to other age groups.

Conclusions: Although overall mortality rates for CML in the United States have decreased considerably between 1999 and 2020, notable differences in mortality persist across different demographic groups. Specifically, older individuals, males, and African Americans exhibit higher mortality rates as compared to younger individuals, females, and White Americans, respectively. Many factors contribute to these disparities. Older adults may face multiple comorbid conditions and reduced treatment tolerance. Males may experience different treatment response and may even be less likely to seek timely medical care as compared to females. African Americans may encounter more limited access to healthcare and socioeconomic disadvantages. Despite significant advancements in reducing CML mortality, addressing the specific challenges faced by certain demographics is essential for achieving further improvements in treatment outcomes in the future.

No relevant conflicts of interest to declare.