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Researchers have been able to set and achieve lower blood pressure
goals in a study group of African Americans whose hypertension
is difficult to control, according to a study published in the
July 22 issue of The Archives of Internal Medicine, one
of the JAMA/Archives journals.
According to the article, hypertension affects 28 percent of
the U.S. population and 35 percent of the African-American population.
The authors write, "[African American] hypertensive patients
[have been] historically perceived to have more severe blood pressure
elevation and to be more resistant to therapy (especially monotherapy
with two of the classes used in this trial, beta-blocker and ACE
inhibitor). Furthermore, because of the study population's lower
education level, fewer financial resources and less positive interaction
with the health care system, long-term maintenance of blood pressure
control was also expected to be a challenge."
Jackson T. Wright Jr. of CWRU and colleagues studied whether
lower blood pressure goals could be achieved by African-American
patients who were being treated for hypertension as part of the
African-American Study of Kidney Disease and Hypertension (AASK).
One thousand ninety four (1,094) African-American participants
in the AASK study aged 18 to 70 years old were assigned to two
target blood pressure groups. The normal mean arterial pressure
(MAP) group was to reach MAP levels of 102 to 107 mm/Hg, approximately
a blood pressure of 140/90 mm/hg. The low MAP group was assigned
to reach MAP levels of 93 mm/Hg or lower, approximately a blood
pressure of 125/75 mm/Hg or lower.
Participants were also randomly assigned to receive ramipril
(an ACE inhibitor), amlodipine (a calcium channel blocker) or
metoprolol succinate (a beta-blocker). Additional medications
were added as needed at the discretion of participants' physicians.
Participants were followed for a total 14 months. Participants
had their blood pressures measured and medications modified if
needed once a month for the first six months of the study and
once a month for the duration of the study. If MAP levels were
5 mm/Hg over the goal MAP level for two consecutive visits, patients
were seen again within two weeks, and their treatments were evaluated
and changes were made to their medications as suggested by their
physicians.
The researchers found that in the group assigned to achieve usual
MAP levels, the percentage that achieved a MAP of 107 mm/Hg increased
from 30.8 percent at the start of the study to 87.7 percent at
14 months into the trial and the percentage of this group that
achieved blood pressures of less than 140/90 mm/Hg increased from
20 percent at the start of the study to 78.9 percent at 14 months.
Among participants assigned to the low MAP group, the percentage
who achieved a MAP level of 92 mm/Hg or less increased from 31.7
percent of participants at the beginning of the study to 73.1
percent at 14 months, and the percentage with blood pressures
of 125/75 mm/Hg increased from 21.5 percent at the beginning of
the study to 41.8 percent at 14 months.
The researchers write, "Participants at or below MAP goal received
an average of 2.7 and 3.5 agents [medications] in the normal MAP
goal and low MAP goal groups, respectively. The AASK participants
above MAP goal are prescribed, on average, a greater number of
agents than those participants at or below goal, suggesting that
resistance to treatment or non-adherence rather than underprescribing
of antihypertensive drugs was the reason for the inability to
reach MAP goal."
"The blood pressure goals set and achieved in AASK participants
clearly demonstrate that adequate blood pressure control can be
achieved even in the most difficult-to-control hypertensive populations,"
the authors conclude.
This study was funded under a cooperative agreement from the
National Institute of Diabetes and Digestive and Kidney Diseases
(NIDDK), (Bethesda, Md), and by grants from other institutions.
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