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4 Interesting Facts of Resistant hypertension
1. Up to 20% of RH is associated with primary aldosteronism, so always screen for this.
2. Up to 50% of RH is associated with at least partial nonadherence to medications. The use of combinations to reduce the total pill burden may help.
3. RH is associated with increased morbidity and mortality.
4. Sodium restriction will assist in BP control.
What is resistant hypertension (RH)? Is it the same as refractory hypertension?
Hypertension is considered resistant if the blood pressure (BP) cannot be reduced below target levels in patients who are compliant with an optimal triple-drug regimen that includes a diuretic typically with an angiotensin converting enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB) plus calcium channel blocker (CCB), or those who have controlled BP but are on four or more medications to achieve BP control.
RH is increasing in frequency due to increased age and obesity. Most patients with hypertension respond favorably to 1 to 3 antihypertensive drugs. RH is present in about 21% of U.S. adults with hypertension, though a much smaller fraction, about 3%, are truly refractory. Refractory hypertension is an inability to control high BP with the use of five or more classes of antihypertensive agents, including a long-acting thiazide-type diuretic, such as chlorthalidone, and a mineralocorticoid receptor antagonist, such as spironolactone.
As with the definition of RH, this diagnosis does not take into account out-of-office BP. Up to 37% of patients labeled as resistant hypertension are actually controlled when BP is measured by 24-hour ambulatory BP monitoring.
Both patients with RH, whether controlled (on four pills) or uncontrolled (on three), and refractory hypertension (uncontrolled on five) have increased cardiovascular risk. This is true for patients with and without chronic kidney disease (CKD). African Americans and patients with CKD are at elevated risk of resistant or refractory hypertension.
Although the definition of RH is currently “in-office BP greater than 140/90,” the SPRINT trial has called into question that BP goal established by clinical practice guidelines, at least in high-risk patients, and the manner of BP measurement. This means that the definition of RH may change too.
If a patient’s BP is uncontrolled on multiple antihypertensive drugs, but one of them is not a diuretic, a diagnosis of RH should be delayed until after a trial of a properly dosed diuretic. It is worthwhile remembering that an “optimal” dose may not necessarily equate to a “full” dose. An optimal dose is the highest dose tolerated by the patient, or a dose governed by concomitant conditions, such as CKD or congestive heart failure.
