Public Release: 

High blood pressure boosts risk of common heart valve disorder

PLOS

Elevated blood pressure is a risk factor for mitral regurgitation, a leakage of one of the heart valves, according to a paper published this week in PLOS Medicine by Kazem Rahimi of The George Institute for Global Health at the University of Oxford, UK and colleagues. The research suggests that this valve disorder, which is increasingly diagnosed wordwide, particularly among older people, is not an inevitable consequence of ageing, as previously assumed, but may be preventable.

In mitral regurgitation, the valve between the two chambers on the left side of the heart doesn't close tightly, allowing blood to leak backwards when the heart muscle contracts. Mitral regurgitation may be associated with palpitations, and in severe cases can cause shortness of breath, fatigue, and swelling of the legs and feet. In the new study, researchers used electronic health records from the UK Clinical Practice Research Datalink (CPRD) between 1990 and 2015 to examine the relationship between systolic blood pressure (BP) and mitral regurgitation. The study included 5.5 million patients with no known cardiovascular disease at the start of the study.

During the 10-year follow-up period, 28,655 patients (0.52%) were diagnosed with mitral regurgitation based on hospital discharge reports or primary care records. Systolic blood pressure (BP) was found to be continuously related to the risk of mitral regurgitation, with each 20 mmHg increase in systolic BP associated with a 26% higher risk of the heart disorder (hazard ratio [HR]: 1.26; 95% confidence interval [CI]: 1.23 to 1.29). Only a small portion of this excess risk could be explained by other conditions that are known to cause mitral regurgitation, such as myocardial infarction or ischaemic heart disease (mediator-adjusted HR 1.22; CI 1.20 to 1.25).

"These findings suggest that BP control may be of importance in the prevention of mitral regurgitation," the authors say.

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Research Article

Funding:

The study was funded by grants from the Oxford Martin School, the National Institute for Health Research, and the British Heart Foundation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing Interests:

KR receives a stipend as a specialty consulting editor for PLOS Medicine and serves on the journal's editorial board. MW is a consultant to Amgen on analyses of routinely collected US health data. JT has received funding from Rhodes scholarship for DPhil study at The University of Oxford. The Rhodes scholarship has no role in the study design or related decisions; JT is director of CHASE (non-government not-for-proft organisation) and previous Director of Libromat (non-government not-for-proft organisation) and secretariat of the Academy of Medical Sciences working group for multimorbidity. NC is supported by a grant from the British Heart Foundation. All the other authors have declared that no competing interests exist.

Citation:

Rahimi K, Mohseni H, Otto CM, Conrad N, Tran J, Nazarzadeh M, et al. (2017) Elevated blood pressure and risk of mitral regurgitation: A longitudinal cohort study of 5.5 million United Kingdom adults. PLoS Med 14(10): e1002404. https://doi.org/10.1371/journal.pmed.1002404

Author Affiliations:

The George Institute for Global Health, University of Oxford, Oxford, United Kingdom
Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
University of Washington, Seattle, Washington, United States of America
The Collaboration Center of Meta-analysis Research, Sabzevar University of Medical Sciences, Sabzevar, Iran
Torbat Heydariyeh University of Medical Sciences, Torbat Heydariyeh, Iran
The George Institute for Global Health, University of Sydney, Sydney, Australia
Department of Epidemiology, Johns Hopkins University, Baltimore, Maryland, United States of America

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