Abstract Body (Do not enter title and authors here): Background: Pulmonary hypertension (PH) is a major contributor to cardiovascular mortality. With the recent lowering of the diagnostic threshold, updated analyses are needed to assess contemporary trends in PH-related mortality, particularly distinctions between Group 1 and Groups 2–5 PH.

Aims: To characterize recent national trends and disparities in PH-related mortality (2003–2023) and examine patterns across WHO Group 1 and Groups 2–5 PH.

Methods: We used CDC WONDER Multiple Cause of Death data to identify U.S. adult deaths (age ≥15) involving PH, classified as Group 1 (ICD-10: I27.0) or Groups 2–5 (I27.2, I27.8, I27.9). Age-adjusted mortality rates (AAMRs) and annual percent changes (APCs) with 95% confidence intervals (CIs) were calculated via Joinpoint regression. Trends were analyzed by year, sex, race, and U.S. region.

Results: From 2003–2023, 512,848 PH-related deaths occurred, 9,068 attributed to PH Group 1 and 503,936 to PH Groups 2-5. Overall AAMRs rose from 6.8 to 9.2 from 2003–2018 (APC: +2.11; 95% CI: 1.70–2.40), peaking at 11.5 in 2021 before declining to 10.9 by 2023 (APC: –1.57; 95% CI: –4.55–2.97). Group 1 PH mortality dropped sharply from 2003 to 2005 (APC: –39.27; 95% CI: –47.77 to –15.97), with AAMRs falling from 0.54 to 0.15. After a stable period until 2018 (APC: +0.79), rates declined further to 0.08 by 2023 (APC: –10.19; 95% CI: –29.37 to –3.27). Groups 2–5 mortality rose from 6.2 in 2003 to 11.4 in 2021 and then had a non-significant slight decline to 10.9 in 2023 (APC: –1.36). Females had higher AAMRs than males across all PH groups. Notably, mortality rose within females in PH Groups 2–5, increasing from 6.4 in 2003 to 11.6 in 2023. In 2023, Non-Hispanic (NH) Black adults had the highest Group 2–5 AAMR (15.1), followed by NH White (11.2) and Hispanic (6.4). For Group 1, NH Black and White adults had equivalent AAMRs in 2023 (both 0.09). Regionally, the South had the steepest Groups 2–5 increase, especially through 2018-2021 (APC: +7.41), while the Northeast had the fastest Group 1 decline from 2017–2023 (APC: –15.06).

Conclusion: PH-related mortality has increased over the past two decades, with Group 1 PH declining and Groups 2–5 rising, especially among females, NH Black adults, and those in the South. The decline in Group 1 may reflect better disease management, while the rise in Groups 2–5 signals ongoing care challenges and the need for targeted interventions for high-risk groups to address ongoing mortality disparities.