MACE fell across Denmark, but income gaps never disappeared
Danish registry data drawn from nearly four decades of follow-up show a long decline in major adverse cardiovascular events across every income group, paired with a stubborn gradient that left the lowest-income residents with the highest event rates throughout the study period. The pattern is clinically familiar and still unsettling: cardiovascular prevention improved at the population level, yet socioeconomic position continued to shape who bore the greatest burden of first hospitalization for acute myocardial infarction, unstable angina, stroke, or heart failure.
The cohort was enormous. Investigators tracked all Danish residents aged 30 years or older who were alive in each year from 1988 through 2023 and had income information available in the current or prior five years. In 1988, the annual study population included 3.06 million people; by 2023, it had grown to 3.85 million. The median age also rose, from 50.8 years to 55.8 years, reflecting an older national population and a changing cardiovascular risk profile over time.
Income quartiles tracked parallel declines in cardiovascular burden
Age-standardized incidence rates declined across all income quartiles, but the lowest-income group consistently remained on top. Among males in the lowest quartile, the rate fell from 191.1 per 10,000 person-years in 1988 to 119.6 in 2023. In the highest-income quartile, the corresponding rate dropped from 153.5 to 85.9 per 10,000 person-years. Females showed the same direction of change: rates declined from 116.0 to 70.4 per 10,000 person-years in the lowest quartile and from 89.5 to 53.1 per 10,000 person-years in the highest quartile.
The absolute improvement is important, but so is the residual separation between groups. Men and women in the lowest income quartile never converged with those in the highest quartile, which suggests that broad gains in prevention, acute care, and secondary prevention have not been evenly distributed. Cardiovascular disease is shaped by more than cholesterol and blood pressure. Access to timely care, exposure to chronic psychosocial stress, smoking patterns, diet quality, work conditions, medication adherence, and competing health priorities can all cluster unevenly by income and exert persistent pressure on vascular risk.
One line stands out in plain clinical terms: the burden declined, but inequality remained embedded in the curve.
Why the gap can narrow without closing
The data fit a familiar pathophysiologic story. Better antihypertensive treatment, statin use, smoking reduction, faster reperfusion for acute coronary syndromes, and more effective heart failure management can push incidence downward across the entire population. Those gains, however, rarely erase the upstream forces that create differential exposure to risk in the first place. People with lower income may face more barriers to preventive visits, more difficulty sustaining long-term medication use, and more intense social and occupational stressors that promote inflammation, autonomic activation, and endothelial dysfunction over time.
In a nation with strong registry infrastructure and broad health coverage, the persistence of this gradient argues that universal access alone does not eliminate cardiovascular inequality. The social patterning of disease appears to survive even when a health system captures nearly everyone. For clinicians, that means income remains a practical risk marker, not because it acts biologically on its own, but because it summarizes lived exposure to multiple cardiovascular hazards that accumulate over decades.
Sex-specific patterns reinforce the same message
The study also separated results by sex, and the overall shape of the findings was consistent in both men and women. Men had higher incidence rates than women across income strata, and both sexes experienced meaningful declines over time. Still, the socioeconomic hierarchy persisted in each sex-specific series.
That consistency matters in the clinic. It suggests that the income gradient is not an isolated artifact of one demographic subgroup. Instead, it reflects a broad structural pattern that touches men and women alike, even as their baseline cardiovascular risk profiles differ. In practical terms, lower-income patients of either sex should be viewed as carrying a higher pretest probability of future MACE, especially when other risk factors are present.
Registry scale gives the trend unusual weight
The strength of this cohort lies in its size, national scope, and long observation window. More than 5.9 million people were captured in the Danish Civil Registration System over the study period, and outcomes were derived from hospital admissions recorded in national registries. That design reduces many of the selection problems that complicate smaller clinical datasets and makes the secular trend hard to dismiss.
At the same time, the endpoint definition focused on first hospital admission for acute myocardial infarction, unstable angina, stroke, or heart failure. The study therefore captures clinically significant events that trigger inpatient care, not every subclinical manifestation of atherosclerotic disease or ambulatory decompensation. The result is a robust measure of major cardiovascular burden, but not a full census of cardiovascular illness in the community.
Prevention gains are real, yet unequal exposure still drives risk
The downward trajectory from 1988 to 2023 offers a clear signal that cardiovascular prevention and treatment have improved at the population level. Fewer first hospitalizations for major cardiovascular events reflect better risk factor control, better acute intervention, and likely earlier detection of disease. Yet the persistent separation between income groups suggests that national progress has been layered unevenly over an unequal social foundation.
For policy and practice, the implication is concrete. Cardiovascular prevention strategies cannot rely only on average population improvement if the highest-risk patients remain concentrated in lower-income groups. Blood pressure control, lipid management, smoking cessation support, diabetes care, and symptom recognition still need to be delivered with an eye toward social disadvantage, because the data show that the lowest-income quartile continues to carry the heaviest event burden even as the overall curve drops.
The study leaves an important clinical question open: which specific policy changes, care models, or preventive interventions can close the gap rather than simply lower the entire curve?