Home is where the real BP readings are.
COLORADO SPRINGS -- Home blood pressure monitoring is emerging as a powerful tool for improving the nation's embarrassingly poor state of hypertension control.
"I would venture to say that, conservatively, at least 30% of the treatment decisions you're making using office blood pressures are based on bad data. In my office I don't use clinic blood pressure readings to make decisions anymore; I use home readings," Dr. Scott Hammond said at the annual conference of the Colorado Academy of Family Physicians.
The notion that office blood pressures are misleadingly off base in 30% or more of patients comes from multiple studies establishing that at least 20% of the general population have white coat hypertension and another 10% or more have masked hypertension--that is, blood pressures that are normal in the physician's office but high elsewhere.
Masked hypertension carries the same stroke and cardiovascular risks as sustained hypertension, as shown in a major 10-year study involving more than 1,300 patients (J. Am. Coll. Cardiol. 2005;46:508-15).
Most patients with masked hypertension are under age 50 years and have prehypertension in the physician's office, but the only way to reliably identify affected individuals is through home blood pressure monitoring (HBPM) or the far costlier ambulatory 24-hour monitoring, observed Dr. Hammond of Westminster, Colo.
He was one of two Colorado family physicians at the conference who described innovative ways they are utilizing HBPM in response to the landmark "Call to Action" jointly issued last year by the American Heart Association, the American Society of Hypertension, and the Preventive Cardiovascular Nurses' Association (Hypertension 2008;52:10-29). The joint scientific statement urged greatly increased use of HBPM in clinical practice.
The second FP, Dr. Bennett Parnes of the University of Colorado, Denver, is project director for a state program whose early success suggests that HBPM can take a big bite out of the disturbingly high national rate of treated but uncontrolled hypertension.
The ACARE (Achieving Cardiovascular Excellence) program funded by the Colorado Department of Public Health and Environment focuses on a low-income, mostly rural, medically underserved hypertensive population. Participants are provided with a free HBPM device with built-in memory and averaging features. They are instructed to take their blood pressure daily at various times, then report their average to project staff monthly by telephone, mail, or e-mail. The staff then sends structured feedback reports to patients and their physicians at 26 participating health clinics.
That's not the standardized HBPM protocol recommended in the Call to Action, but that discrepancy doesn't bother Dr. Parnes.
"We figure if we can get this population to take their blood pressures at all, we're successful," he explained.
More than 1,000 ACARE participants are regularly reporting their HBPM data. After 8 months, the proportion of patients at target has climbed from 35% to 52%. Perhaps more importantly, among the roughly 700 participants not at goal at baseline, mean blood pressures improved from 146/85 mm Hg to 135/82 mm Hg and 42% reached target levels.
Moreover, among the subset of diabetic participants not at target initially, mean blood pressures declined from a baseline of 146/85 mm Hg to 136/79 mm Hg after 8 months and 26% have achieved target pressures, Dr. Parnes continued.
In a semistructured interview with 58 participating patients, half reported increasing their amount of exercise as a result of participation in ACARE, two-thirds changed their diet, and 57% increased their medication adherence, he reported.
An ACARE provider survey demonstrated that 95% of clinicians believe HBPM has improved the quality of blood pressure care in their practice. Three-quarters indicated that they now believe the home readings if the office and home blood pressures are different. That practice, Dr. Parnes noted, is strongly evidence based. Five prospective studies have compared home and office blood pressures for predicting cardiovascular events; all five showed home blood pressure is a significant predictor, and four of the five concluded that it's a stronger predictor than office readings.
Dr. Hammond has taken a very different approach in incorporating HBPM into his suburban family medicine practice, which serves as a formal pilot for the coming national patient-centered medical home project. He relies on HBPM not only to guide therapy for patients with established hypertension, like in ACARE, but also to diagnose hypertension more accurately. He follows the structured guidelines for HBPM that have been endorsed by all of the world's major hypertension societies. The guidelines include limiting diagnostic HBPM to 1 week's duration, with measurements taken at specific times of day. (See box.)
"It's not just, 'Go home and measure your blood pressures and send me a list.' It has to be structured. You have to know what you're getting. This is a real paradigm shift for us, to say, 'I'm trusting data that is not in my control,'" he observed.
Dr. Hammond rents HBPM devices that have the guidelines built in, so patients can measure their blood pressure only at the recommended times. About half of his patients go that route; the rest opt to purchase a machine from among those listed at www.dableducational.com as having been validated by an independent testing organization. The devices typically cost $30-$100.
Patients for whom a blood pressure treatment decision needs to be made receive an educational sheet explaining the value of HBPM before Dr. Hammond enters the examining room. It cuts down on questions.
Patients interested in HBPM then make an appointment to see his medical assistant on another day for training in proper blood pressure measurement and the HBPM protocol. It's an educational service that takes about 10 minutes, which he bills as a 99211.
He typically has patients with established hypertension do 1 week of HBPM four times per year to monitor the effectiveness of their medication.
It's well documented that a quarter of Americans with hypertension are unaware of it. Another 35% of hypertensive patients are aware but untreated, and of those with treated hypertension, more than 60% are not at target. Dr. Hammond called that a national disgrace and an indictment of a severely dysfunctional health care system.
"What profession, what industry, would tolerate those numbers? You can say, 'It's my patients' fault--they're not taking their meds.' But you know something? There are practices that are getting 60%-70% control rates. So you can't point your finger at your patients. This is our problem. This is our failure," he declared.
Dr. Hammond is a consultant to Microlife Medical Home Solutions, which markets HBPM devices.
Doing HBPM by 'The Book'
The following steps are taken to identify a final blood pressure average during a 1-week test period:
* Take two blood pressure measurements 1 minute apart during 69 a.m. Average them.
* Take two blood pressure measurements 1 minute apart during 69 p.m. Average them.
* Average the morning and evening measurements for an all-day average.
* Throw out the first day results.
* Average all of the other morning, evening, and all-day measurements for the week. This final average is used to decide how to manage the patient.
Source: HBPM Call to Action, also known as the Picketing Paper (Hypertension 2008;52:10-29)
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|Title Annotation:||CARDIOVASCULAR MEDICINE|
|Comment:||Home is where the real BP readings are.(CARDIOVASCULAR MEDICINE)|
|Publication:||Family Practice News|
|Date:||May 1, 2009|
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