Disparities and Trends in Non-Hodgkin Lymphoma Mortality in Elderly Adults between 1999 and 2020

Introduction: Non-Hodgkin Lymphoma (NHL) has the highest incidence of all hematologic malignancies in those 65 years of age or older. More than half of all patients diagnosed with NHL are above the age of 65 with increased age being associated with an elevated risk of development. NHL tends to have a better prognosis relative to other hematologic malignancies with a 5-year survival of 72%. However, disparities are present in mortality in patients with NHL. Our aim was to evaluate for demographic and regional temporal trends in NHL mortality within the United States between 1999-2020 for those who are 65 years or older as currently no study has analyzed these trends in this population group.

Methods: The CDC WONDER database was used to determine mortality statistics for patients, 65 years or older, with an underlying cause of death from Non-Hodgkin Lymphoma (ICD-10 codes C82.0-85.0) between 1999 and 2020. Age-adjusted mortality rates (AAMR) were calculated per 100,000 deaths and were additionally stratified by demographic and geographic variables such as race (NH White, NH Black, Hispanic, NH Asian, and NH American Indian/Alaskan Native), sex, census region (Northeast, Midwest, South, and West), and population density (rural, suburban, and urban). Joinpoint regression software was used to identify temporal trends. Average annual percent change (APC) was considered statistically significant if p< 0.05.

Results:

Between 1999 and 2020, NHL accounted for 348,047 deaths in individuals 65 years of age or older. Over this period, the AAMR decreased by 35% going from 48 in 1999 to 31 in 2020, and there was a significant decrease in APC of –2.1(p<0.05).

In 1999, males had an AAMR of 59.3 which was 34% higher than the female AAMR of 42. By 2020, this difference had increased to 53% with males having an AAMR of 40.7 and females having an AAMR of 23.5. This trend was seen in the APC where females had a larger significant drop in APC at–2.5 (p<0.05) whereas males only had a significant drop in APC at –1.8 (p<0.05).

When evaluated by race, Non-Hispanic White individuals had the highest AAMR recorded at 51.2 but also had the largest decrease in AAMR dropping nearly 38% between 1999 and 2020. Non-Hispanic Black individuals had the lowest AAMR recorded in 2020 at 19.3. All groups experienced a significant drop in APC; however, NH White individuals had the largest drop in APC at –2.0 (p<0.05). The smallest drop in APC was seen in both NH Black and Hispanic individuals at –1.3 (p<0.05).

By population density, those in suburban populations had the highest AAMR of 48.8, and urban populations had the lowest AAMR of 46.5. Although all three groups experienced a significant drop in APC, the trend did not mirror the pattern seen in AAMR. Urban populations had the largest drop in APC at –2.3 (p<0.05), but rural populations had the smallest drop in APC at –1.8 (p<0.05).

By census region, it was found that the Midwest had the largest AAMR in 1999 at 52.8 and continued to hold the highest AAMR till 2020 at 34.7. The West had the lowest AAMR in 1999 at 45.4, but the South had the lowest AAMR in 2020 at 29.7. The APC, however, was found to be significant for all regions, but had the largest drop in the NE at –2.4 (p<0.05). All other census regions (Midwest, South, and West) had the same APC of –2.0 (p<0.05).

Conclusion: Since 1999 there has been an overall decrease in mortality from NHL; however, the burden and rate of mortality is disproportionate amongst various demographic groups. Those that were male, NH White, from suburban or rural populations, and the Midwest were found to have experienced the highest mortality rate from NHL relative to their counterparts. Given the early asymptomatic presentation of NHL alongside limited risk factors for NHL, the use and identification of potential demographic background characteristics for earlier detection may help reduce mortality for those at greater risk.