Abstract
INTRODUCTION: Chronic lymphocytic leukemia (CLL) is the most prevalent white blood cell malignancy in the United States and accounts for about 1 in 3 new cases of leukemia in the US. The increased risk of pneumonia in CLL patients is linked to impaired immunity and immunosuppression from treatment which in turn increases susceptibility to disease causing pathogens. In this study, we aim to evaluate the mortality trends due to CLL and pneumonia in the US and in turn conceptualize the prevention and care strategies.
METHODS: Using the Centre for Disease Control and Prevention Wide‐Ranging Online Data for Epidemiologic Research (CDC‐WONDER), we retrospectively analyzed annual age‐adjusted mortality rates (AAMR) per million from 1999 to 2023 in patient with CLL (icd code; C91.1) and Pneumonia (icd code J12.0-J18.9). Temporal trends were analyzed, and, Average Annual Percentage Change (AAPC) and Annual Percentage Change (APC) were calculated using the Join Point regression model across variations in demographics (sex, race) and regional subgroups. APC trends from three periods—Pre-pandemic (1999–2018), Pandemic (2018–2021), and Post-pandemic (2021–2023)—were analyzed to yield stratified results.
RESULTS:- During the 25-year study duration, a total of 22,968 deaths were reported due to CLL and Pneumonia in the United States. The overall trend was declining with the AAPC of -2.98% (Cl -4.31 to -1.63, p = 0.000017), with significant APC trends in all three periods (-4.87%, 30.22%, and -24.72).
According to gender based analysis, males reported higher deaths compared to females (n males; 14,489 vs n females; 8,488), the trend favored also females as the rate of decline was more prominent among them, with AAPC of -3.56% (vs males; -2.81%). The APC analysis revealed that trend was overall negative, except in the pandemic era when it reached staggering high values of 29.60% in males and 28.35% in females.
Racially, the overall trend was quite similar between both stratified races; whites and African Americans (AA), however the decline was slightly higher in whites with AAPC of -2.62%, in contrast to -2.28% in AAs. The APC trend was, however, only significant in Whites with mortality incline in pandemic era, followed by a sharp decline in post-COVID-19 era, consistent with overall trend (29.48% in 1999-2018, and -21.86% in 2019-2020). AAs only exhibited one significant trend in the pre-pandemic times with recorded APC of -3.94%.
Geographically, all regions showed significant negative trends, but it was more pronounced in western region (-3.23%) followed by the northeast (-2.96%). Pre-pandemic decline was more notable in the west with APC of -5.18%. Conversely, Midwest and south exhibited highest rates of increase during COVID-19 with a drastic APC rise of 34.32% and 33.59%, whereas in the post-pandemic era, the trend favored the south as it reported APC of -25.55%.
Area wise disparities were also observed with rural populations showing more negative AAPC then urban populations (AAPC rural; -4.30% vs Urban; -2.62%) till 2020. APC trends were also same for rural areas, however urban populations showed a significant declining trend in 1999-2018 with APC of -4.62 and an inclining trend in the rest of period with APC 18.53%.
CONCLUSION:- To summarize, overall mortality due to CLL and pneumonia has declined in the last 25 years, however disparities remain among different racial and demographic groups, reflecting the need for targeted intervention and better policies. Notable inclines in the APC during pandemic show that COVID-19 had a significant effect on mortality and was an integral driving factor that resulted in steep incline in values, the similar decline in the post COVID-19 period also supports the same hypothesis. Rural areas showing worse outcomes can be attributed to higher smoking prevalence.
