Washington, DC - Hypertension is a "neglected disease," according to a report released by the Institute of Medicine (IOM) . Despite high blood pressure being the cause of death in one of six American adults and the greatest single risk factor for death from cardiovascular disease, millions of Americans are developing, living with, and dying from hypertension. The decade from 1995 to 2005 saw a 25% increase in the death rate from high blood pressure, the report notes.
"We are failing to translate our public-health and clinical knowledge into effective prevention, treatment, and control programs," asserts the Committee on Public Health Priorities to Reduce and Control Hypertension in the US Population. Their report, published by the National Academies Press, offers recommendations for changes by individuals, physicians, and policies to prevent and control high blood pressure and associated health problems.
Among the committee’s recommendations are strengthening collaboration between the Centers for Disease Control and Prevention (CDC) and related agencies to include hypertension in their lifestyle-improvement efforts ; monitoring and reducing sodium intake ; improving the reporting of hypertension to determine general population and subgroup trends ; and improving quality of care and removing economic barriers to effective antihypertensive treatments.
Down with sodium, up with potassium
The report notes that 87% of American adults ingest more than 2400 mg/day of sodium (no more than 1500 mg/day is recommended for people middle-aged or older, African Americans, and those with hypertension). Barriers to reducing dietary sodium were recently explored in a heartwire feature story. A strategy recommended to the Division of Heart Disease and Stroke Prevention (DHDSP) is the use of potassium/sodium-chloride combinations to simultaneously reduce sodium and increase potassium intakes.
Using estimates based on 31 trials of sodium reduction and data indicating that 87% of the American population consumes excess sodium, the report estimates that the prevalence of hypertension could be cut by 5% to 8% if everyone currently on a high-salt diet decreased their salt intake by about 4.5 g/day.
"Over eight in 10 Americans eat more salt in their diet than is recommended. And almost everyone consumes too little potassium," said Dr David W Fleming, chair of the committee, during a February 22, 2010 briefing at the National Academies’ Keck Center in Washington, DC. "The committee recommends that the CDC take a strong and active leadership role, working with industry to implement strategies to reduce salt in our diet, promote the intake of potassium-rich fruits and vegetables, and consider advocating for the greater use of potassium/sodium combinations as a means of simultaneously reducing sodium and increasing potassium intake."
The effects of potassium supplementation have varied across studies, but data indicate that if the entire population increased its potassium intake to 4700 mg/day, the prevalence of hypertension could be reduced as much as 4% to 7%. The proportion of hypertension currently attributed to low potassium intake is around 17%.
High potassium intake, however, can itself be problematic. Dr Lawrence J Appel (Johns Hopkins University, Baltimore, MD), who attended the briefing, said that "in general, it appears that diets that are both low in sodium and rich in potassium are the best diets in terms of lowering blood pressure and controlling hypertension, [but] there are some caveats. There are patients with kidney disease, but it has to be pretty advanced before you get to problems with potassium. And there are patients with advanced heart failure [in whom] you’re concerned about it. Typically, those are patients who are being cared for and monitored, so . . . certainly, for the general population, but also for most patients with hypertension who don’t have the problems I mentioned, you’re not going to get any problems from dietary potassium," Appel said.
The committee recommends that the DHDSP and related agencies focus on preventing hypertension by reducing overweight and obesity, increasing physical activity, reducing sodium intake, and increasing the intake of fruits, vegetables, whole grains, and especially foods rich in potassium.
Nonadherence : A patient and physician problem
The DHDSP was also urged to identify better ways of analyzing and reporting data on hypertension over time and establishing norms for data collection and analysis and the reporting of these data-with a particular focus on children, the elderly, minorities, and socioeconomic groups for which fewer data are available.
Of particular interest were the committee’s findings on patients’ nonadherence to treatment and physicians’ nonadherence to guidelines laid out by the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC). Although the JNC advises starting treatment when systolic blood pressure exceeds 140 mm Hg or when diastolic blood pressure exceeds 90 mm Hg, many physicians are much less aggressive. Most cases of uncontrolled hypertension were in older adults with mild systolic hypertension and with frequent contact with their physicians and access to healthcare.
"It was quite striking, actually, that clinicians do a pretty good job of controlling diastolic blood pressure ; it’s systolic blood pressure that they’re not aggressively treating, and especially isolated systolic hypertension," said committee member Dr Corinne Husten. "There could be a variety of reasons. When I was in medical school, we were taught that you don’t treat a high top number because older people need that head of steam to get the blood through those hardened arteries. The data since then have shown that’s really not true."
Husten noted that clinicians might also be concerned about the side effects of medication in older people and whether a full dosage should be used.
High costs of antihypertensives
The IOM report also highlighted the financial barriers to lowering blood pressure. Studies have shown that the cost of medications to patients is significantly related to patient adherence ; this is especially evident in patients with low income, chronic illness, and multiple prescriptions. The committee advocates lowering or eliminating the costs of antihypertension drugs under Medicare and Medicaid.
At the policy level, recommendations urge state and local public-health agencies to emphasize populationwide approaches and to integrate hypertension prevention into programs to influence obesity prevention, increase physical activity, and encourage healthy diets.
On a more positive note, the committee suggested that hypertension has the "advantages" of being objectively diagnosed and measured, having low-cost treatments already available, having results that can be easily measured and reproduced, and having the disease respond rapidly to interventions.
"Here is a place where, as a result of new work that has been done, we now not only think we can make a difference, but we have scientific studies in both the public-health arena and in the clinical arena that show we can make a difference," concluded Fleming.
After completion of the report, Husten joined the US Food and Drug Administration as senior medical advisor, Center for Tobacco Products (October 2009). Appel has done clinical research and trials that led to some conclusions in the report and has given invited talks at pharmaceutical companies, but does not feel he has conflicts of interest. One of his National Institutes of Health-sponsored studies received partial support from King-Monarch, which provided medication.
The complete contents of Medscape Medical News, a professional news service of WebMD, can be found at www.medscape.com, a website for medical professionals.
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1. Institute of Medicine. A Population-Based Policy and Systems Change Approach to Prevent and Control Hypertension. Washington, DC : The National Academies Press, 2010. Available at www.nap.edu.
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