Hypertension after JNC-VI: Target early control
Identify risk levels to reduce complications
Uncontrolled hypertension (HT) means increased utilization and cost. A quarter of American adults are hypertensive, yet only half of those receive drug therapy, and only 45% of treated patients achieve their target blood pressure (BP). This is especially important for older patients with isolated systolic HT who are at high risk of stoke. In any age group, suboptimal control results in end-organ damage and heart failure.
Ben Hubbard, MD, a cardiologist at Michigan Heart & Vascular Institute in Ann Arbor, MI, says the Sixth Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC-VI) has affected his practice in a couple of ways: For patients with coronary disease - especially if they have diabetes - he is now targeting 130-135 mmHg as desired BP measures as opposed to 140 mmHg and above. He also is more aggressive with beta blockers and angiotensin-converting enzyme (ACE) inhibitors now.
The authors of JNC-VI point out that the cost of drugs can interfere with HT control since they account for 70% to 80% of HT treatment costs.1 Newer yet unproven agents are expensive and push that percentage even higher. The document encourages cost-cutting measures such as the use of combination tablets and generic drugs.
JNC-VI updates the previous JNC-V with new treatment strategies and a system of stratifying HT patients by stage - 1, 2, 3 - and risk group - A, B, C - to guide treatment decisions. (See Table 5, p. 30.) JNC-VI defines stage 1 as 140-159/90-99 mmHg, stage 2 as 160-179/100-109 mmHg, and stage 3 as ³180/³110. Risk groups are based on the presence of risk factors such as high blood cholesterol and on related organ damage.
For patients with uncomplicated HT, JNC- VI recommends diuretics and beta blockers as first-line treatment. Other drugs, sometimes in combination with diuretics or beta blockers, are recommended for patients with complications. For the first time, the guideline establishes "compelling indications" for specific drugs when patients have certain clinical conditions. For example, older people with isolated systolic HT should be treated first with diuretics. Patients with diabetes, kidney damage, and high BP should begin treatment with ACE inhibitors.
Heart attack in conjunction with HT is a compelling indication for beta blockers and, in certain instances, ACE inhibitors. Heart failure should first be treated with ACE inhibitors and diuretics. The JNC-VI recommends that ACE inhibitor therapy may have favorable effects on Types 1 and 2 diabetes with proteinuria and renal insufficiency. Recommen da tions for such patients are to treat promptly and reduce BP to under 130/85 mmHg. Heart failure should be treated with an ACE inhibitor, used alone or in conjunction with digoxin or diuretics.
The new guideline reiterates earlier warnings from the National Heart, Lung and Blood Institute about negative heart effects of short-acting nifedipine (New York City-based Pfizer's Procardia XL), a type of calcium channel blocker. This drug should be used only with great caution, it states, if at all.
JNC-VI suggests that certain long-acting calcium channel blockers - including long-acting nifedipine - are alternates for older patients with isolated systolic HT, the most common form of HT in the elderly. Some experts dispute the "alternate" designation, citing new findings that suggest long-acting calcium antagonists are highly effective for treating isolated systolic HT in the elderly. In general, JNC-VI advises that most patients should be started on low doses of the initial drug, preferably in long-acting formulas. If a diuretic is not chosen as the first drug, it can be used to enhance the effects of other medications.
(HT drugs are shown in Table 8 on p. 29 and above. New formulations are available also, shown in Table 9, p. 31. Combinations of low doses of two agents from different classes have been shown to work well and minimize the likelihood of dose-dependent adverse effects. Very low doses of a diuretic - for example, 6.25 mg of hydrochloro thiazide - can potentiate the effect of another agent without producing adverse metabolic effects.
Low-dose combinations of an ACE inhibitor and a nondihydropyridine calcium antagonist may reduce proteinuria more than either drug alone. Combinations of a dihydropyridine calcium antagonist and an ACE inhibitor induce less pedal edema than does the calcium antagonist alone. In some instances, drugs with similar modes of action may provide additive effects, such as metolazone and a loop diuretic in renal failure.
Reference
1. The Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure and the National High Blood Pressure Education Program Coordinating Committee. The sixth report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC-VI). Arch Intern Med 1997; 157:2,413-2,446.
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