Long COVID linked to higher hypertension risk in Swedish cohort study

Overview

The Conversation reports on a large Swedish cohort study that links long COVID to an increased risk of hypertension, even among people who had mild initial infections. The study analyzed diagnoses, healthcare visits, hospitalizations and prescriptions from the MIRACLE-S cohort in Stockholm County, focusing on adults aged 18 to 65 without pre-existing hypertension.

• Long COVID diagnosed in 8,365 participants (0.7%) between October 2020 and January 2025.
• Overall hypertension incidence in the cohort during follow-up: 18%.
• Among those with long COVID, hypertension incidence was 22–23% during follow-up.
• After adjusting for age, socioeconomic status and other health conditions, long COVID was associated with a 14% higher risk of hypertension than those without long COVID.

Author: The Conversation.

Overview

In a comprehensive observational study published by The Conversation, researchers used data from the MIRACLE-S cohort to examine the long-term cardiovascular effects of COVID-19 in Stockholm County, Sweden. The analysis included more than 1.2 million adults aged 18 to 65 who did not have pre-existing hypertension and had not been hospitalized for COVID-19 at baseline. Participants were followed from late 2020 through January 2025 to assess the incidence of long COVID and subsequent development of hypertension. This setup allowed the investigators to focus on milder infections and the potential lasting impact of SARS-CoV-2 on blood pressure regulation and cardiovascular health.

Methods and Population

The MIRACLE-S cohort traces diagnoses, healthcare visits, hospitalizations and prescription information. By excluding individuals with pre-existing hypertension and those hospitalized for COVID-19, the study aimed to isolate the long term effects of milder infections. Between October 2020 and January 2025, 8,365 individuals were diagnosed with long COVID (0.7% of the cohort). During the follow-up, 18% of all participants were diagnosed with hypertension. The incidence of hypertension in the long COVID group hovered around 22% to 23% across the follow-up period. Adjusted analyses, controlling for age, socioeconomic status and the presence of other health conditions, indicated that long COVID was associated with a 14% higher risk of developing hypertension compared with those without long COVID.

Key Findings Across Subgroups

The study explored differences by sex and age. Hypertension incidence among long COVID patients was similar in women and men when averaged across the full cohort. However, within the long COVID group, hypertension occurred in 16% of women and 24% of men, suggesting sex-specific patterns in how long COVID may influence blood pressure. Age amplified risk: the association between long COVID and hypertension was stronger in older age groups, a finding that aligns with known cardiovascular aging processes such as arterial stiffening and increased vascular resistance. The authors note that age-related cardiovascular changes could interact with long COVID related alterations in vascular function to elevate blood pressure.

Additionally, the researchers found that diabetes amplified the association, implying potential overlapping cardiometabolic mechanisms linking long COVID, hypertension, and diabetes. They caution that these findings require confirmation in future research and that observational design limits causal inferences. The study did not have data on treatments started during follow-up that might affect blood pressure, underscoring the need for more granular future analyses.

Interpretation and Implications

The authors describe a plausible mechanistic link between long COVID and hypertension. Other work has shown that COVID-19 can impair arterial function and alter blood pressure for up to three years in healthy adults. Although the Swedish study could not measure blood pressure or arterial stiffness directly, it supports the idea that long COVID may contribute to cardiometabolic changes that raise hypertension risk over time. The findings carry potential clinical implications: hypertension is a major modifiable cardiovascular risk factor, and recognizing long COVID as a risk amplifier could encourage earlier blood pressure monitoring and preventive strategies in patients with lingering symptoms post infection.

The researchers advocate for more proactive blood pressure assessment in people with long COVID, particularly those with diabetes or older age. They also highlight the need for future work to adjust for treatments started after infection and to confirm the observed associations in other populations. Overall, the study contributes to a growing understanding that long COVID can have lasting impacts beyond fatigue and dyspnea, extending to the regulation of blood pressure and cardiovascular health.

Limitations and Future Directions

As an observational analysis, the study cannot establish causality. It could not directly measure blood pressure or arterial stiffness, and it lacked information on specific treatments affecting hypertension risk during follow-up. Future studies should incorporate direct cardiometabolic measurements and adjust for therapeutic interventions to clarify pathways linking long COVID and hypertension. Replication in diverse populations is also essential to determine generalizability of these results.

Clinical and Public Health Significance

Hypertension remains a leading modifiable risk factor for cardiovascular disease, including coronary heart disease. If long COVID contributes to hypertension risk, clinicians may need to integrate cardiovascular risk assessment and hypertension screening more thoroughly into post-COVID care, especially for patients with additional risk factors such as diabetes. These insights could inform public health guidance on screening and early intervention strategies for populations recovering from COVID-19.

Conclusion

The Swedish MIRACLE-S cohort analysis adds to the accumulating evidence that long COVID can affect cardiovascular health by increasing hypertension risk, particularly among older adults and individuals with diabetes. While more research is needed to confirm causality and to understand underlying mechanisms, the findings underscore the importance of monitoring blood pressure in people with long COVID and considering early intervention to mitigate long-term cardiovascular risk.