Abstract Body (Do not enter title and authors here): Background:
Pericardial Diseases (PD) have become a significant cause of morbidity and mortality over the last two decades. They contribute secondarily to deaths associated with other primary illnesses and can present clinically as pericarditis, pericardial effusion, and hemopericardium. Despite treatment advances, U.S. mortality trends for PD are unexplored.

Aim:
This study aims to assess the trends in PD-related deaths in the United States from 1999 to 2022.


Methods:
PD-related deaths in adults aged 25 years and above were identified through CDC WONDER database from 1999 to 2022 from multiple causes of death. Crude mortality rates and age-adjusted mortality rates (AAMR) per 100,000 population were determined. Joinpoint regression was used to examine changes in trends and annual percentage change (APC) overall, and then stratified by sex, ethnicity, and age groups.


Results:
A total of 105,536 deaths occurred from PD between 1999 to 2022. Overall, AAMR related to PD decreased from 1999 (2.4) to 2012 (1.7) (APC -2.73 [95% CI, -3.09 to -2.36]), then gradually increased until 2019 (2.0) (APC 2.92 [95% CI, 1.57 to 4.29]), followed by a sharp increase until 2022 (APC 7.65 [95% CI, 4.42 to 10.99]). After an initial decline, APC in AAMR increased in women (4.36) starting in 2012, while in men, it decreased significantly until 2011 (-2.26), followed by a slight increase until 2016 (1.05), and then a marked increase from 2016 to 2022 (4.19). After an initial decline, AAMR increased among non-Hispanic (NH) Blacks (APC 5.42) and NH Whites (APC 4.95) starting in 2014, among Hispanics (APC 4.10) from 2012 to 2022, and among NH Asian or Pacific Islanders (APC 2.4) from 2007 to 2022. Mortality rates have been steadily increasing across all age groups over the last decade, with the highest increase seen recently in the 85+ age group (2017-2022 APC 9.09 [95% CI, 6.50 to 11.76]).

Conclusion:
PD-related mortality has increased over the last decade. Mortality among males, NH Blacks, and the 85+ age group has been growing at a faster rate than any of the other groups. These results highlight the need for further investigation into the factors contributing to the observed disparities and trends in PD mortality rates.