Increased Medicare hospital spending is associated with reduced acute aortic dissection mortality in the United States.

Abstract

In recent decades, national acute aortic dissection (AAD) mortality rates have decreased, whereas Medicare expenditures have risen, raising questions about the value of care. We investigated the longitudinal association between Medicare expenditures (both hospital and physician) and age-adjusted AAD mortality at a population level, accounting for geographic variation. We conducted a retrospective, longitudinal ecological study using publicly available, aggregate data from 1999 to 2020. The primary outcome was the annual state-level, age-adjusted AAD mortality rate from the Centers for Disease Control and Prevention Wide-ranging Online Data for Epidemiologic Research database. Primary predictors were state-level, per-beneficiary Medicare hospital (part A) and physician (part B) expenditures for index AAD hospitalizations from the Centers for Medicare & Medicaid Services. After excluding states with suppressed data, 38 states were included in the final analysis. A multivariable linear regression model was constructed to identify the adjusted effects of spending and geography on age-adjusted AAD mortality. From 1999 to 2020, the average national age-adjusted AAD mortality rate significantly decreased from 6.2 to 4.3 deaths per 100,000 population (P < .0001), whereas per-beneficiary hospital expenditures steadily rose. After adjusting for year and geography, increased spending in both categories was significantly associated with reduced mortality. Every $1000 increase in annual hospital (part A) spending per beneficiary was associated with a decrease of 0.479 age-adjusted deaths per 100,000 (95% confidence interval: -0.672 to -0.286; P < .0001). Similarly, every $1000 increase in physician (part B) spending was associated with a decrease of 0.646 age-adjusted deaths (95% confidence interval: -0.886 to -0.405; P < .0001). Significant geographic disparities persisted, with the Southwest, Southeast, and New England regions demonstrating better mortality outcomes than other U.S. regions. Increased Medicare spending for both hospital-level infrastructure (part A) and physician services (part B) is significantly associated with reduced age-adjusted AAD mortality at a population level. These findings suggest that both system-level investment and robust access to specialist care are linked to survival. However, these benefits are not distributed equally across the United States. These findings represent statistical associations, not a causal link, and must be interpreted with caution given the study's ecological design.