Adults with hypertension who were vaccinated for COVID-19 with at least one booster were more than twice as likely as vaccinated and boosted individuals without hypertension to be hospitalized for severe COVID-19, according to data from more than 900 individuals.
“We were surprised to learn that many people who were hospitalized with COVID-19 had hypertension and no other risk factors,” said Susan Cheng, MD, MPH, director of the Institute for Research on Healthy Aging in the department of cardiology at the Smidt Heart Institute, Los Angeles, and a senior author of the study. “This is concerning when you consider that almost half of American adults have high blood pressure.”
COVID-19 vaccines demonstrated ability to reduce death and some of the most severe side effects from the infection in the early stages of the pandemic. Although the Omicron surge prompted recommendations for a third mRNA vaccine dose, “a proportion of individuals who received three mRNA vaccine doses still required hospitalization for COVID-19 during the Omicron surge,” and the characteristics associated with severe illness in vaccinated and boosted patients have not been explored, Joseph Ebinger, MD, of Cedars-Sinai Medical Center, Los Angeles, and colleagues wrote.
Previous research has shown an association between high blood pressure an increased risk for developing severe COVID-19 compared to several other chronic health conditions, including kidney disease, type 2 diabetes, chronic obstructive pulmonary disease, and heart failure, the researchers noted.
In a studyin the researchers identified 912 adults who received at least three doses of mRNA COVID-19 vaccine and were later diagnosed with COVID-19 during the surge in infections from the Omicron variant between December 2021 and April 2022.
A total of 145 of the individuals were hospitalized (16%); of these, 125 (86%) had hypertension.
Patients with hypertension were the most likely to be hospitalized, with an odds ratio of 2.9. In addition to high blood pressure, factors including older age (OR, 1.3), chronic kidney disease (OR, 2.2), prior myocardial infarction or heart failure (OR, 2.2), and longer time since the last vaccination and COVID-19 infection were associated with increased risk of hospitalization in a multivariate analysis.
However, the increased risk of severe illness and hospitalization associated with high blood pressure persisted, with an OR of 2.6, in the absence of comorbid conditions such as type 2 diabetes, kidney disease, and heart failure, the researchers emphasized.
“Although the mechanism for hypertension-associated COVID-19 risk remains unclear, prior studies have identified delayed SARS-CoV-2 viral clearance and prolonged inflammatory response among hypertensive patients, which may contribute to greater disease severity,” they wrote.
The findings were limited by several factors, including the use of data from a single center and lack of information on which Omicron variants and subvariants were behind the infections, the researchers noted.
However, the results highlight the need for more research on how to reduce the risks of severe COVID-19 in vulnerable populations, and on the mechanism for a potential connection between high blood pressure and severe COVID-19, they said.
Given the high prevalence of hypertension worldwide, increased understanding of the hypertension-specific risks and identification of individual and population-level risk reduction strategies will be important to the transition of COVID-19 from pandemic to endemic, they concluded.