April 7 (HealthDay News) -- Lifestyle factors and medication recommendations are among the topics covered in the guidelines for treating resistant hypertension released Monday by the American Heart Association.

In patients with resistant hypertension, their blood pressure remains above the target level despite taking three medications to lower it. High blood pressure that's under control but requires four or more medications to treat it, is also considered resistant to treatment.

Studies suggest that as many as 30 percent of people with high blood pressure may have resistant hypertension. Older age and obesity are two major risk factors for the condition, which is likely to become more common in the United States as the population ages and becomes heavier, noted the guideline writing committee.

People with resistant hypertension have a high cardiovascular risk and often have multiple health conditions that complicate efforts to manage their blood pressure.

The first step is to determine whether a person actually has resistant hypertension, which isn't the same as uncontrolled hypertension, the committee said. Successful treatment of resistant hypertension requires consideration of lifestyle factors that contribute to the problem, diagnosing and treating secondary causes, and using multiple drug treatments effectively.

Lifestyle factors noted by the committee included weight, salt intake and alcohol consumption. Obesity is associated with more severe blood pressure and losing weight can lower blood pressure and reduce the number of medications needed to control blood pressure. High dietary salt intake is common among patients with resistant hypertension. In patients with general high blood pressure, reducing salt intake can lower blood pressure. Heavy alcohol intake is also associated with resistant hypertension. Research shows that reducing alcohol consumption can help lower blood pressure.

The committee also listed a number of health conditions that can contribute to resistant hypertension. They include: obstructive sleep apnea, renal parenchymal disease, primary aldosteronism and renal artery stenosis. Treating these conditions may improve blood pressure control.

Medications were the third area covered by the committee. They said the use of drugs that increase blood pressure, such as non-steroidal anti-inflammatory drugs (NSAIDs), should be reduced or halted, if possible, in patients with resistant hypertension.

The committee noted that diuretics are often underused in people with resistant hypertension. They also said some patients may benefit from adding mineralocorticoid receptor antagonists (MRAs) to their treatment regimens. MRAs treat primary aldosteronism, which is found in about 20 percent of people with resistant hypertension.

"The benefit of mineralocorticoid receptor antagonists in treating resistant hypertension has only been recently confirmed," writing committee chair Dr. David A. Calhoun, a professor of medicine in the Vascular Biology and Hypertension Program at the University of Alabama in Birmingham, said in a prepared statement.

"Hypertension specialists are likely using them to a greater degree, but they are probably not being broadly used to address this problem. Using MRAs requires special biochemical monitoring, particularly to measure blood levels of potassium due to the risk of hyperkalemia [a condition caused by abnormally high potassium levels in the blood]," he said.

Multi-drug regimens, dose timing and patient adherence to medications are also addressed in the guidelines, which were published online in Hypertension.

SOURCE: American Heart Association, news release, April 7, 2008