KEY POINTS FOR CLINICIANS
- Only 53% of hypertensive patients are being treated, and only 24% have their hypertension under control.
- The first step in planning the treatment of a patient with essential hypertension is to categorize the patient’s risk status.
- The target blood pressure of patients who have diabetes or renal failure should be less than 130/85.
- Diuretics are safe, well tolerated, effective, relatively inexpensive, and convenient for initial drug treatment of hypertension in patients who do not have concomitant illness.
- Alpha-adrenergic blockers should be used with caution in the treatment of hypertension.
- Ambulatory blood pressure measurements predict cardiovascular events more closely than clinic blood pressure measurements.
Hypertension is arbitrarily defined as diastolic blood pressure (DBP) of 90 mm Hg or higher, systolic blood pressure (SBP) of 140 mm Hg or higher, or both, on 3 separate occasions. Essential hypertension is hypertension without an identifiable cause. Essential hypertension, also known as primary or idiopathic hypertension, accounts for at least 95% of all cases of hypertension.
According to the third National Health and Nutrition Examination Survey (NHANES III), approximately 60% of the 50 million Americans with hypertension are at increased risk for cardiovascular disease resulting from uncontrolled hypertension. This is because only 53% of hypertensive patients are being treated and only 24% have their hypertension under control.1 Physicians must play an active role in identifying and treating hypertension.
In an earlier Applied Evidence article2 an approach to the diagnosis of hypertension was presented. This article reviews the treatment of essential hypertension in adults and the prognosis of untreated hypertension. Risk stratification, alternative therapies, lifestyle modification, drug therapy, and prognosis will each be reviewed sequentially.
Risk stratification
The decision to treat hypertension and the choice of treatment is affected by the patient’s risk of morbidity and mortality if the blood pressure remains untreated or under-treated. According to the recommendations of the sixth report of the Joint National Committee on the Prevention, Diagnosis, Evaluation, and Treatment of High Blood Pressure (JNC-VI), the first step in planning treatment of a patient with essential hypertension is to categorize the patient’s risk status.3 The patient is placed in 1 of 9 treatment categories according to his or her blood pressure category, cardiovascular risk factors, and evidence of end-organ damage found during the initial evaluation (Table 1). Once the treatment category is identified, initial treatment should begin (Figure 1). Subsequent treatment depends on the patient’s response to initial treatment (Figure 2).
Patients should be monitored regularly to be sure they do not develop signs and symptoms that would place them in a different category and mandate more aggressive treatment. After a patient’s blood pressure has been controlled for 1 year, it may be possible to decrease the dose or the number of antihypertensive drugs—especially among patients who make significant lifestyle changes.4
The effectiveness of therapy varies depending on the patient’s cardiovascular risk. The New Zealand Guidelines Group has developed a helpful risk calculator based on the Framingham Heart Study for estimating a patient’s cardiovascular risk. This calculator incorporates sex, age, systolic blood pressure, smoking status, total cholesterol, high-density lipoprotein cholesterol, presence or absence of diabetes, and presence or absence of electrocardiogram evidence of left ventricular hypertrophy. This helpful risk calculator may be downloaded from the Web site of the New Zealand Guidelines Group at http://www.nzgg.org.nz/library/gl_complete/bloodpressure/appendix.cfm#app3. Alternatively, the University of Sheffield Medical School has developed tables to estimate an individual’s risk of heart disease based on cardiovascular risk factors including age, sex, cholesterol level, and presence or absence of smoking, hypertension, and diabetes—Sheffield tables.5 Software for handheld computers (Palm and PocketPC) that helps you estimate risk is available at www.jfponline.com.
Regardless of the method used, the benefit of treatment increases steadily as the patient’s current cardiovascular risk increases. With a 5-year cardiovascular risk of less than 2.5%, more than 120 patients have to be treated for 5 years to prevent 1 cardiovascular event; this number decreases to 25 patients with a risk of between 5% and 10%, and only 13 with a risk of between 20% and 24%.6 It is tempting to assume that the benefit of hypertension treatment is related to reduction in blood pressure whether achieved by drug therapy, lifestyle modification, or alternative therapy. However, this has not been established and it is important to consider the evidence supporting the benefit of each of these therapeutic options (Table 2).
TABLE 1
HYPERTENSION RISK STRATIFICATION AND TREATMENT CATEGORIES
| Blood Pressure Category | Risk Group A* | Risk Group B* | Risk Group C* |
|---|---|---|---|
| High-normal (130 – 139/85 – 89) | Lifestyle modification† | Lifestyle modification | Lifestyle modification and drug therapy |
| Stage 1 (140 – 159/0 – 99) | Lifestyle modification (12-month trial) | Lifestyle modification (6-month trial) | Lifestyle modification and drug therapy |
| Stage 2 or 3 (≥ 160 / ≤100) | Lifestyle modification and drug therapy | Lifestyle modification and drug therapy | Lifestyle modification and drug therapy |
| *Risk groups: A = no risk factors, end-organ damage, or clinical cardiovascular disease; B = 1 risk factor other than diabetes, no end-organ damage, and no clinical cardiovascular disease; C = Diabetes, end-organ damage, or clinic cardiovascular disease. | |||
| † Lifestyle modification should be included in the treatment plan of all patients receiving drug therapy. | |||