Background
Hematological malignancies confer profound immunosuppression, thereby predisposing patients to life-threatening
infectious complications. Pneumonia remains a leading cause of mortality in this population.

Objective
To characterize temporal trends in pneumonia-related mortality among patients with hematological malignancies
from 1999 to 2020, stratified by sex, race, and census region, through Joinpoint regression analysis.

Methods
We analyzed the CDC WONDER Multiple Cause of Death database for decedents with colisted hematological
malignancies (C81–C96) and pneumonia (J09–J18) from 1999 to 2020. Age-adjusted mortality rates (AAMRs)
per 100000 were stratified by sex, race/ethnicity (White, Black/African American, Asian/Pacific Islander, and
Hispanic/Latino), and US Census region. American Indian/Alaska Native data were excluded because most annual
estimates were flagged as unreliable by CDC WONDER, owing to small death counts. APC was estimated with
the NCI Joinpoint regression program (P <0.05).

Results
A total of 121182 deaths occurred (72532 male; 48650 female). All subgroups showed a significant decline from
1999 to 2018, followed by a reversal from 2018 to 2020 coinciding with the COVID-19 pandemic. Male patients had
higher AAMRs than female patients throughout (1999: 5.17 vs 2.46; 2020: 3.69 vs 1.68). Both significantly declined
from 1999 to 2018 (male APC: −3.14%; female: −2.95%) and rose significantly from 2018 to 2020 (male APC:
+13.70%; female: +9.53%). Asian/Pacific Islander patients showed an uninterrupted decline across the entire
study period (APC: −2.15%). All other racial groups showed a 2018 inflection: Black/African American (1999–2018:
−2.35%; 2018–2020: +17.15%), White (−2.94%; +11.42%), and Hispanic/Latino, with the steepest rise (2018–2020
APC: +21.68%). Regionally, all significantly declined from 1999 to 2018 (APC: −2.67% to −3.26%). The 2018–
2020 rise was statistically significant in the Northeast (+11.55%), Midwest (+16.50%), and South (+13.56%); the
West showed a similar upward trend, but it did not reach statistical significance (APC: +7.61%).

Conclusion
Pneumonia-related mortality in patients with hematological malignancies significantly declined across all
subgroups from 1999 to 2018. The uniform 2018 inflection underscores the COVID-19 burden on this immunocompromised
population. The nonsignificant rise in the West and uninterrupted decline among Asian/Pacific
Islander patients warrant further investigation. Persistent sex and racial disparities highlight the need for targeted
preventive strategies.