Researchers at Karolinska Institutet have found that people with long COVID face an increased risk of developing cardiovascular disease even if their initial infection did not require hospital care. The population-based study, published in eClinicalMedicine, shows that conditions such as cardiac arrhythmias and coronary artery disease occur more frequently in individuals diagnosed with long COVID compared with those without the condition.
Over a follow-up period of up to four years, 18.2% of women and 20.6% of men with long COVID experienced a cardiovascular event, compared with 8.4% and 11.1%, respectively, among those without long COVID. After adjusting for demographic and clinical factors, women with long COVID had just over twice the risk of cardiovascular disease, while men had approximately one-third third higher risk.
“We found that cardiac arrhythmias and coronary artery disease were more common among both women and men with long COVID. In women, there was also an increased risk of heart failure and peripheral vascular disease. However, no clear association was found between long COVID and stroke,” said lead author Pia Lindberg of Karolinska Institutet.
The research was conducted using the Multimorbidity Integrated Registry Across Care Levels in Stockholm (MIRACLE-S), which includes data from around 2.5 million residents. Investigators identified more than 1.2 million individuals aged 18 to 65, including nearly 9,000 diagnosed with long COVID between October 2020 and January 2025. To isolate the effects of long COVID, the study excluded individuals who had been hospitalized during acute infection or who had pre-existing cardiovascular disease. The researchers then applied Cox proportional hazards models to estimate the risk of major cardiovascular outcomes, including myocardial infarction, heart failure, arrhythmias, stroke, and peripheral arterial disease, adjusting for demographic, lifestyle, and mental health factors.
The decision to focus on non-hospitalized individuals reflects a gap in earlier research. Previous studies have largely concentrated on patients with severe COVID-19 requiring hospital or intensive care, leaving uncertainty about risks among those with milder infections managed in the community. Because hospitalized and non-hospitalized individuals differ in baseline cardiovascular risk, disease severity, and care pathways, the researchers aimed to examine these groups separately. This approach allowed them to assess whether long COVID itself is associated with increased cardiovascular risk independent of acute disease severity.
Prior evidence had suggested a link between COVID-19 and cardiovascular complications, including myocardial infarction, stroke, arrhythmias, and heart failure. Large cohort studies reported elevated rates of these outcomes following infection, with risks persisting for up to a year. However, many of these studies combined hospitalized and non-hospitalized populations or focused on severe cases, limiting insight into community-managed long COVID. The researchers wrote, “Long COVID has emerged as a global health challenge, with increasing evidence of cardiovascular sequelae. Most previous studies have focused on hospitalized cohorts, whereas cardiovascular risk in community-managed long COVID cases remains less explored.”
This study adds to the literature by providing population-based evidence that long COVID is associated with increased cardiovascular risk even after mild-to-moderate infection. By restricting the cohort to individuals without prior cardiovascular disease and analyzing outcomes separately by sex, the findings highlight differences in risk patterns. Cardiac arrhythmias showed the largest increase, particularly among women, while coronary artery disease was elevated in both sexes. Heart failure and peripheral arterial disease were increased among women only. The researchers wrote, “Long COVID is associated with increased risk of incident cardiovascular disease, particularly cardiac arrhythmias, heart failure, and coronary artery disease. These findings underscore the need for systematic follow-up and integration of long COVID into cardiovascular risk assessment.”
The mechanisms underlying these associations remain under investigation, but proposed explanations include endothelial dysfunction, chronic inflammation, thrombogenicity, and immune-mediated injury. The persistence of elevated risk over a follow-up period extending up to 40 months suggests that long COVID may involve sustained physiological changes rather than a short-term post-viral effect. The researchers wrote, “This population-based cohort study demonstrates that individuals who developed long COVID after mild-to-moderate infection have an elevated risk of future cardiovascular disease analyzed as a composite outcome.”
Clinically, the findings indicate that long COVID should be considered a risk factor for cardiovascular disease beyond hospitalized populations. The data support more systematic monitoring of individuals with long COVID, particularly in primary care settings where many cases are managed. Sex-specific differences observed in the study suggest that risk assessment and follow-up strategies may need to account for variation in presentation and outcomes between women and men. The results also highlight the potential for under-recognition of cardiovascular complications in patients who were not hospitalized during acute infection.
The researchers noted that while absolute risks remain modest, the relative increases are comparable to established cardiovascular risk factors. This has implications for integrating long COVID into existing risk assessment frameworks and for planning healthcare services. Future work will focus on further clarifying mechanisms, validating findings in other populations, and refining strategies for early detection and prevention of cardiovascular disease in people with long COVID.
