A Scientific Statement from the American Heart Association Professional Education Committee of the Council for High Blood Pressure Research

Date: April 7, 2008

Summary:  An estimated 20 to 30 percent of clinical trial participants with high blood pressure suffer from a “resistant” form of the disorder which makes it difficult for physicians to treat these patients and keep their  blood pressure at a safe level. Understanding the causes of resistant hypertension will likely lead to improved prevention and treatment and is essential to improving long-term clinical management of the disorder.  

Journal: Hypertension

Journal citation: Hypertension. 2008;51:000-000 Epub online April 7, 2008

Read the original article: http://hyper.ahajournals.org/cgi/reprint/HYPERTENSIONAHA.108.189141

Why it’s important: High blood pressure puts people at risk of developing heart disease and stroke. Reducing blood pressure can reduce risk. However, according to clinical trials, an estimated 20 to 30 percent of people with high blood pressure have difficulty reducing their blood pressures to safe levels. The problem will only get worse as the population ages and more people become obese. Understanding how to diagnose resistant high blood pressure and determining the best treatment methods can save hearts, brains and lives.

What’s already known: High blood pressure is considered resistant to treatment when pressure remains high, even though the patient takes three different blood pressure-lowering drugs. A patient who takes four or more medicines to control blood pressure and is successful in doing so is also considered resistant to treatment. Patients with this problem may benefit from more intensive study of their problems. The exact percentage of people who have resistant high blood pressure is unknown. However, in a recent analysis of the federal National Health and Nutrition Examination Survey (NHANES), among participants being treated for hypertension, only 53 percent were controlled to the recommended level of less than 140/90 mm Hg. This percentage was even greater in people older than age 75.

Some people have uncontrolled hypertension; others have resistant hypertension. The two are not the same. People whose high blood pressure is uncontrolled often do not take their medication as needed or are not treated properly with the right combinations of medicine. People with resistant hypertension don’t respond to treatment that’s adequate for most people.

How this study was done: This is not a study. It’s a review of studies done in this area of investigation, and suggests what types of studies need to be done to identify resistant hypertension.

What was found: The number of people with resistant hypertension is growing. However, even people with very high blood pressure can be treated effectively. In fact, some studies show that effective treatment can reduce the risk of death or disability by 90 percent over 18 months of care by a physician. People with resistant high blood pressure are often older, obese, suffer from chronic kidney disease, have diabetes, have an oversized left ventricle (the major pumping chamber of the heart), are of African-American descent and are female.

People with uncontrolled high blood pressure usually don’t take their medicine as prescribed, don’t monitor their blood pressure adequately and are more likely to have higher blood pressure when it’s measured in the doctor’s office (the “white coat” effect).  People who take non-steroidal anti-inflammatory drugs (such as ibuprofen, naproxen or prescribed medications), decongestants (for nasal congestion), diet pills, prescribed steroid medicines such as prednisone, cortisone or hydrocortisone, birth control pills, herbal compounds such as ephedra or ma huang, cyclosporine (an anti-rejection drug) or erthyropoietin (a drug that stimulates production of red blood cells) may also have blood pressure increases. Sleep apnea (disrupted or obstructed breathing while sleeping) and other health conditions also can raise blood pressure. Eating too much salt also can contribute to resistant high blood pressure, and can reduce the efficacy of blood pressure medicines. Some people are more sensitive to the effects of salt than others. Heavy alcohol consumption can also raise blood pressure.

Doctors should verify that patients truly have treatment resistance. This includes home or worksite blood pressure measurement, or 24-hour blood pressure measurement, to rule out the “white-coat” effect. Further blood tests can identify other contributing conditions. Treatment for sleep apnea (stopping breathing while sleeping) or other contributing conditions will help control blood pressure. Lifestyle changes, including weight loss and dietary modifications, can also help control blood pressure. Patients with severe hypertension might benefit from going to a physician who specializes in treating high blood pressure. 

More research is needed to identify the causes of resistant hypertension. However, because people with high blood pressure also suffer from heart disease, such research can be difficult.

The bottom line: If you have blood pressure that’s above 140/90 mm Hg, seek treatment from a doctor who is skilled in treating the problem and has special training in this area. Patients with resistant hypertension may benefit from referral to a hypertension specialist. Taking medications can help but it may also be necessary to modify risk factors, such as losing weight and making dietary changes.



This content is reviewed regularly. Last updated 05/27/08.