Cardiovascular Hospitalizations Burden the US More than Denmark

Hospitalizations for cardiovascular events were 1.5-fold higher in adults aged ≥65 in the United States, compared with Denmark, with notable disparities by social risk factors, including income level, according to a recent cross-sectional study.1

The study, involving nearly 60 million US adults and 2 million Danish adults, found the burden of myocardial infarction (MI) and heart failure (HF) hospitalizations significantly higher in the US, but ischemic stroke hospitalizations slightly lower, with mixed hospitalization-related mortality across all conditions.

“Our findings provided important public health insights regarding the burden of cardiovascular disease (CVD)–the leading cause of death globally–in 2 higher-income countries with distinct health systems,” wrote the investigative team, led by Rishi K. Wadhera, MD, MPP, MPhil, section of health policy & equity, Richard A. and Susan F. Smith Center for Outcomes Research, Beth Israel Deaconess Medical Center. “There are several potential reasons for the higher overall burden of cardiovascular hospitalizations that we observed in the US.”

Wadhera and colleagues set out to measure the burden of cardiovascular events in the US against other high-income countries with a distinct healthcare system, such as Denmark. The fragmented nature of US healthcare can create barriers to preventive care, including a lack of access to screen cardiometabolic risk factors in midlife, leading to greater events down the line.2

Given the rising prevalence of cardiometabolic risk factors in US adults, social risk factors, including poverty and low educational attainment, are strongly linked to a greater CVD risk in later life. On the other hand, universal health systems in Denmark emphasize primary and preventive care services, which may allow for earlier diagnosis and treatment of CVDs.3

For this analysis, the investigative team centered on individual-level data for adults ≥65 years in the US and Denmark from January 2021 to January 2022 to allow assessment of hospitalizations for acute CVDs, 30-day hospitalization-related mortality rates, and the impact of income-based inequities on these outcomes. Low income was defined as dual eligibility for Medicare and Medicaid in the US (~15% of the population) and the lowest 15th percentile of household income over the previous 3 years in Denmark.1

The primary outcome of the analysis was annual age- and sex-standardized hospitalization rates per 1000 US and Danish adults, both overall and separately for MI, HF, and stroke. The secondary analysis focused on 30-day all-cause mortality rates after hospitalization in both countries.

A total of 58,614,110 US adults aged ≥65 (mean age, 74.6; 54.9% female) were identified for analysis, of whom 1,171,058 (2.0%) were hospitalized for a cardiovascular event. In Denmark, 1,176,542 adults aged ≥65 (mean age, 75.3 years; 53.9% female) were identified and 16,305 (1.4%) were hospitalized with a cardiovascular event.

Upon analysis, Wadhera and colleagues found overall age- and sex-standardized cardiovascular hospitalizations significantly higher in the US, compared with Denmark (risk ratio [RR], 1.50; 95% CI, 1.47–1.52). The difference remained significant for MI hospitalizations (RR, 1.56; 95% CI, 1.51–1.61) and HF hospitalizations (RR, 2.37; 95% CI, 2.31–2.43), but not ischemic stroke hospitalizations (RR, 0.90; 95% CI, 0.88–0.93).

Income analysis revealed US cardiovascular hospitalization rates more than 2-fold higher in low-income populations, compared with higher-income (RR, 2.38; 95% CI, 2.25–2.47) groups, and particularly for HF hospitalizations (RR, 2.76; 95% CI, 2.59–2.93). For Denmark, a smaller income-based gap was identified, with a slightly higher rate of cardiovascular hospitalizations in low-income groups (RR, 1.45; 95% CI, 1.39–1.50).

Further analysis showed 30-day all-cause mortality rates slightly elevated in the US, compared with Denmark (RR, 1.12; 95% CI, 1.06–1.17), particularly for MI (RR, 1.81; 95% CI, 1.61–2.05) and stroke (RR, 1.38; 95% CI, 1.25–1.54). However, HF-related mortality rates were lower in the US than in Denmark (RR, 0.79; 95% CI, 0.73–0.85), suggesting the potential for differences in acute care delivery.

“Although hospitalization rates were significantly higher in the US, 30-day mortality rates were significantly lower, which might reflect variation in the delivery of acute care between the 2 nations’ health systems as well as underlying differences in the severity of illness among those hospitalized with HF,” Wadhera and colleagues wrote.

References

1. Berg FH, Lassen MCH, Vaduganathan M, et al. Cardiovascular Hospitalizations Among Older Adults in the US and Denmark. JAMA Cardiol. Published online February 05, 2025. doi:10.1001/jamacardio.2024.5303

2. McClellan M, Brown N, Califf RM, Warner JJ. Call to Action: Urgent Challenges in Cardiovascular Disease: A Presidential Advisory From the American Heart Association. Circulation. 2019;139(9):e44-e54. doi:10.1161/CIR.0000000000000652

3. Aggarwal R, Yeh RW, Joynt Maddox KE, Wadhera RK. Cardiovascular Risk Factor Prevalence, Treatment, and Control in US Adults Aged 20 to 44 Years, 2009 to March 2020. JAMA. 2023;329(11):899-909. doi:10.1001/jama.2023.2307