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Approximately 50 million people in the United States are affected by hypertension.1 Individuals who are normotensive at 55 years of age are estimated to have a 90% lifetime risk for developing hypertension.1 With no decline in sight, the time to control blood pressure is now.
Many patients are unaware of their hypertension because disease presentation is not evident until target organ damage has occurred. Of the patients who have begun treatment, >70% have not achieved adequate blood pressure control.2 Health care providers, including pharmacists, must be able to counsel patients appropriately so that they may effectively care for themselves.3-11
Control of blood pressure depends on accurate blood pressure measurement. Home blood pressure monitoring may accomplish the following aims:
Home blood pressure monitors also serve as visual cues for patients and help as positive reinforcement tools for drug compliance.12 The information patients receive from self-monitoring should encourage them to take charge and to be responsible for their disease state.
Currently, there are 3 major types of blood pressure monitors: the mercury sphygmomanometer, the aneroid manometer, and the digital/electronic device. The mercury sphygmomanometer involves a tubular gauge, a mercury reservoir, and a manually inflated cuff. This device incorporates gravity to measure blood pressure; it is the most accurate of the 3 types. A stethoscope, however, must be used to auscultate Korotkoff's sounds; thus, this device is less user-friendly for most patients than the others. Accidental shattering of the mercury reservoir may lead to toxicities if the mercury comes into direct contact with skin or if it is ingested.
The aneroid manometer consists of a numbered dial and a manually inflated cuff. This device uses a mechanical bellows and lever system rather than mercury. Aneroid meters are less expensive but are less accurate than mercury sphygmomanometers.13 Aneroid meters also require that users be able to note Korotkoff's sounds; thus, they are less favorable for home use.
Digital blood pressure monitors include either a completely automatic or a semiautomatic inflatable cuff. Although some digital devices are able to measure blood pressure on fingers and wrist, only those used above the forearm are accurate.14 Digital devices display blood pressure on a clear and readable screen that is available with large and dark font characters, which are easy for patients with deteriorating vision to read. Digital devices are the least accurate, but a high degree of correlation has been documented when compared with clinician readings.15 The simplicity of digital devices makes them the ideal choice for home blood pressure monitoring. Patients should regularly bring digital devices to clinicians' offices to ensure their accuracy as compared with mercury sphygmomanometers and aneroid manometers.14
A vital aspect of home blood pressure monitoring is having the correct cuff size. Inaccuracies may result if cuffs are not fitted properly. The standard-size cuff is recommended for patients with an arm circumference of 9 to 13 inches. For patients with arms measuring 14 to 17 inches, a larger-size cuff should be used. An appropriate-size cuff should encircle at least 80% of the arm.14
Patients should be seated quietly in a chair for at least 5 minutes, with their feet uncrossed on the floor and their arm supported at heart level.14 Initially, patients should be told to measure blood pressure in both arms to detect any unusual differences. After this initial reading, the measurement of the arm with the higher reading is considered adequate.14 Taking at least a single or double reading in the morning and evening is sufficient.14, 16 The average of these measurements should be recorded on a patient log.
Patients who use stethoscopes should be reminded that the systolic blood pressure (SBP) is the point at which the first of 2 or more sounds is heard and that the diastolic blood pressure (DBP) is the point immediately before the disappearance of sounds. Patients who are >50 years of age should be counseled that it is more important to control SBP than DBP, because cardiovascular disease risk factors are more evident with higher SBP1,17 (Table 1).
The goal blood pressure is a critically important target to establish (Table 2). Clinicians should give both written and verbal goals to patients. According to the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7),1 the blood pressure goal for most patients without comorbid diseases is <140/90 mm Hg. For hypertensive patients with diabetes mellitus or chronic kidney disease, the goal is to control blood pressure to <130/80 mm Hg.1
The JNC 7 recommends that patients without comorbid diseases such as diabetes, congestive heart failure, or angina be treated with a thiazide diuretic for stage 1 hypertension. For patients with stage 2 hypertension, a thiazide diuretic combined with an angiotensin-converting enzyme inhibitor, an angiotensin receptor blocker, a beta-blocker, or a calcium channel blocker is recommended. The treatment standards encourage the use of 2 low-dose antihypertensive agents from different classes, rather than 1 high-dose medication, to maximize efficacy while minimizing adverse effects.
Exercise and diet are the mainstays of hypertension control (Tables 3 and 4). The Dietary Approaches to Stop Hypertension (DASH) diet has proved efficacious in reducing SBP in patients by 8 to 14 mm Hg. This eating plan encourages high intake of fruits, vegetables, and low-fat dairy products with a reduced content of total and saturated fats. The JNC 7 recommends that patients involve themselves in aerobic exercise for at least 30 minutes per day on most days of the week. For approximately every 20 pounds of weight lost, it is believed that patients may reduce their SBP by 5 to 20 mm Hg.
Patients should be advised that excess salt ingestion will increase blood pressure. Salt restriction could make the difference between needing only 1 rather than 2 antihypertensive agents. The JNC 7 also recommends that male patients consume no more than 2 alcoholic drinks per day and female patients no more than 1 drink per day. Limiting alcohol consumption may decrease SBP by 2 to 4 mm Hg.
The Role of the Pharmacist
With the wealth of knowledge that patients possess and the drug information they obtain from family, friends, Internet sites, and other sources, it is easy to understand that there is great potential for misinformation. Pharmacists need to educate patients accurately and appropriately so that they are able to care for themselves effectively.
Dr. Pham is an assistant professor of pharmacy practice at Arnold & Marie Schwartz College of Pharmacy and Health Sciences, Long Island University.
For a list of references, send a stamped, self-addressed envelope to: References Department, Attn. A. Stahl, Pharmacy Times, 241 Forsgate Drive, Jamesburg, NJ 08831; or send an e-mail request to: firstname.lastname@example.org.