For decades, common medical wisdom has
been “the lower the better” in treating the approximately one in three people
in this country who have high blood pressure. But does that approach result in
reduced risk for dangerous heart events?
In a study published in the June 16 online edition of
JAMA Internal Medicine, researchers at Wake Forest Baptist Medical Center found
that lowering systolic blood pressure below 120 does not appear to provide
additional benefit for patients. Systolic pressure is the top number in a standard
blood pressure reading (e.g., 120/80).
“Frequently we treat patients’ blood pressure to the
lowest it will go, thinking that is what’s best,” said Carlos J. Rodriguez,
M.D., associate professor of public health sciences at Wake Forest Baptist and
lead author of the study.
“Our observational study found that treating to low
pressures doesn’t provide any benefit to patients with regard to reducing risk
of dangerous heart events like heart attack, heart failure and stroke. This
calls into question the notion that lower is better.”
Previous studies had documented a progressive increase in
heart disease risk as systolic blood pressure (SBP) rose above 115, but it was
not known whether SBP lower than 120 in patients with hypertension (HTN)
lowered the risk of heart failure, stroke and heart attack.
In this study, a total of 4,480 participants from the
Atherosclerosis Risk in Communities Study were followed for 21 years for
development of a cardiovascular event. Measurements of SBP were taken at baseline and
at three-year intervals. SBP was categorized as elevated (140 or greater),
standard (120 -139) or low (less than 120). The study findings were independent
of baseline age, gender, diabetes status, body mass index, cholesterol level,
smoking status and alcohol intake. A cardiovascular event was defined as heart
failure, ischemic stroke, heart attack or death related to coronary heart
The researchers found that among people with high blood
pressure, once SBP is below 140, lowering it below 120 did not further reduce
the risk of cardiovascular events.
“Our study found that the optimal blood pressure range
for people with hypertension is120-139, which significantly reduces the risk of
stroke, heart attack or heart failure,” Rodriguez said. “These findings suggest
that you don’t need to go lower than that to have the benefits.”
Rodriguez said that his study was not a clinical trial
and its results need to be confirmed; noting that a large clinical trial under way
called SPRINT should either confirm or refute the findings.
Funding for the study was provided by the National Heart,
Lung, and Blood Institute grant award R01HL104199, and by contracts for the Atherosclerosis
Risk in Communities Study.
Co-authors are: Katrina Swett, M.D., of Wake Forest
Baptist; Sunil K. Agarwal, M.D., Johns Hopkins University; Aaron R. Folsom,
M.D., University of Minnesota; Ervin R. Fox, M.D., University of Mississippi
Medical Center; Laura R. Loehr, M.D., Wayne D. Rosamond, M.D., and Patricia P.
Chang, M.D., of University of North Carolina at Chapel Hill; and Hanyu Ni,
M.D., of National Heart, Lung, and Blood Institute.