Variable Blood Pressure Linked to Cardiovascular Events

Researchers have found that greater blood pressure variability is associated with higher risks of acute cardiovascular events such as stroke or even death among hypertensive men and women.

Investigators from the University of Alabama at Birmingham School of Public Health compared the highest versus lowest levels of between-visit variability in systolic blood pressure readings, finding there were greater risks of coronary heart disease, stroke, hospitalization for heart failure, and all-cause death through a maximum of 5.7 years of follow-up, according to Paul Muntner, MD, TITLE at UAB and co-author of the study. These findings were consistent across various subgroups, including in patients who were and were not at their blood pressure goals.
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To examine the relationship between visit-to-visit blood pressure variability, Munter and colleagues studied data from the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT), which included more than 42,000 participants from 623 sites in the United States, Canada, Puerto Rico, and the U.S. Virgin Islands.

The analysis excluded patients randomized to the prematurely terminated doxazosin arm of the trial, those who had cardiovascular events before the 28-month visit, and those who had blood pressure data from fewer than 5 visits, leaving 20,656 for the final cohort. The authors defined blood pressure variability in the primary analysis according to the standard deviation of systolic readings from visit to visit. During follow-up, there were 1,096 cases of coronary heart disease, 1,845 deaths, 535 strokes, and 824 cases of heart failure.

After multivariate adjustment for potential confounders such as medication adherence, the number of antihypertensive classes being taken, and average systolic blood pressure, increasing blood pressure variability was associated with increasing risks of all outcomes analyzed. The findings did not vary based on age, sex, race, diabetes status, whether blood pressure was controlled to less than 140/90 mm Hg, or randomized assignment to chlorthalidone, amlodipine, or Lisinopril, and were consistent when the researchers used other definitions of variability.

The findings were presented at the American Society of Hypertension 2014 Annual Meeting, held May 16 – 20 in New York, where Muntner said he and his colleagues are now looking into mechanisms underlying the visit-to-visit variability in blood pressure.

“Blood pressure variability itself may not have prognostic importance, but it could be a marker of the underlying vascular disease that physicians can treat,” said Muntner, noting arterial stiffness and diastolic dysfunction as causes of variability.

Clinicians, he said, may want to look into the reasons for the variability when they see it, adding that changes to medication regimens may be able to address variability.

——Mark McGraw