Doctors Unsure When to Treat High Blood Pressure in
Diabetics
Uncertainty stems from ambiguous standards,
competing demands and overlapping health problems
It’s crucial for people with
diabetes to keep their blood pressure under control – below
130/80 if possible.
May 20, 2008 – For people with
diabetes,
high blood pressure poses a special threat, multiplying their risk
of heart attacks, strokes and kidney problems. But a new study finds
that even when people with diabetes show up in their doctor’s office
with a high blood pressure reading, there’s only a 50-50 chance that
each of them will get some sort of attention for it.
That might mean a change to their medications, or a
plan to follow up a few weeks later to see if the reading is still high.
The fear is that this lack of response to high
blood pressure readings at clinic visits could mean that patients’
pressures will keep getting worse.
The study takes a look at possible causes of
clinical inertia and finds little evidence supporting the idea that
providers are just “ignoring” blood pressure problems.
What really seems to have an impact on treatment
decisions is plain old uncertainty about whether the blood pressure is
really elevated, or providers being occupied with other medical issues.
Providers might need to spend the visit addressing more pressing
problems, some of which, like pain, may be contributing to elevated
blood pressures. Or, they might take another reading and conclude
there’s no need for action. Or, patients may report that their pressure
readings at home have been fine.
In the meantime, says Kerr, “While there are many
guidelines about treating hypertension, there is an amazing lack of
clarity and guidance about how many blood pressures should be taken at a
clinic visit, whether those blood pressures should be averaged or
whether just the lowest should be used, and how to incorporate home
blood pressure readings in decisions to intensify medications. As long
as this confusion exists, we may not make progress in treating
hypertension.”
The study was performed among 1,169 people with
diabetes who were seen in VA primary care clinics over a one-year
period, at nine different sites in three states.
All the patients had a blood pressure reading over 140/90 mm Hg at the
start of their clinic visits. The national goal for people with diabetes
is less than 130/80 mm Hg. (For people without diabetes or kidney
problems, the goal is less than 140/90, which is considered the cutoff
for Stage I hypertension.)
Of these patients, 573, or 49 percent, received a
change in their blood pressure treatment at the same clinic visit –
either a new prescription for a medication, a change in the dosage of an
existing medication or medications, or a documented plan to follow up
within four weeks. While this rate is higher than has been reported in
other settings, there still appears to be room for improvement.
As part of the study, the researchers asked both
patients and providers to complete brief questionnaires before the end
of the day of the clinic visit. Most of the 92 providers who saw the
patients were physicians, but they also included nurse practitioners and
physician assistants. This prospective design allowed the researchers to
look at all the different variables associated with providers’ tendency
to adjust blood pressure treatment in reaction to the high initial
reading.
Their analysis revealed findings that have
implications for how patients, and clinicians, measure and react to
blood pressure in clinics. For instance, there was wide variation among
clinics in the likelihood that providers would order a treatment change
in patients with a reading over 140/90 mm Hg.
Uncertainty about what the patient’s blood pressure
was one of the largest factors. Providers variably repeated the blood
pressure check once the patient was in the exam room, and not
surprisingly were much less likely to change treatment if the new
reading was lower than 140/90 mm Hg. Only 13 percent of such patients
had a treatment change, compared with 61 percent of those with a high
second reading, or who didn’t get one.
“Providers clearly ‘trust’ their own reading more
than they do the reading taken at the clinic intake point,” suggests
Hofer. “But there is no evidence that supports that approach. In fact,
the literature suggests that provider measurements are less reliable and
subject to large biases relative to independent measures by nurses using
electronic blood pressure cuffs.”
Additionally providers responded to their patient’s
own report about what kind of readings he or she was getting using a
home blood pressure monitor. Only 18 percent of patients who told their
providers their home measurements had been below 140/90 mm Hg received a
treatment change, compared with 52 percent who said their pressures at
home had been high, or who didn’t report at-home monitoring.
While at-home monitoring can be important, Kerr
says, the fact of the matter is that there is no standard for how often
to monitor and how to record home pressure readings over time. Further,
patients might preferentially report only the “normal” blood pressures
and ignore the out-of-range values.
Patients should talk to their doctors about how
often to monitor and record their blood pressure and look at averages
over time, she says. If their average is above the target, it might be
time to change treatment.
Finally, another major factor interfering with a
patient’s chances of getting a treatment adjustment turned out to be
somewhat predictable: attention to other issues. If a patient’s chief
reason for coming to the clinic was unrelated to their diabetes or their
blood pressure – for instance, if they were seeking treatment for pain –
they were much less likely to receive attention for their blood
pressure. The same was true for clinic visits where a patient’s
medications weren’t discussed.
The team is continuing its study to see how long it
takes for patients to get a treatment change. They hope their work will
help guide further hypertension guidelines, and standardization of
clinic practices. And that, they hope, will help millions of diabetes
patients protect their long-term health.
In addition to Kerr and Hofer, the researchers
include Brian Zikmund-Fisher, Ph.D., Mandi Klamerus, MPH, Usha
Subramanian, M.D., M.S., and Mary M. Hogan, Ph.D., RN. Funding for the
study came from the VA, and from the
Michigan Diabetes Research and Training Center. Reference: Annals of
Internal Medicine, May 20, 2008, Vol. 148, No. 10.
