SAN FRANCISCO — Approximately 16% of 264,697 patients in a community-based practice network had treatment-resistant hypertension in 2007.
The true prevalence may be 8%-11% after adjustment for pseudoresistance, which previous studies suggest accounts for 30%-50% of suspected treatment-resistant hypertension, Dr. Brent M. Egan said at the annual meeting of the American Society of Hypertension.
At the same time, many of these patients are undertreated. Only two or fewer antihypertensive medications were prescribed for 60% of 49,043 patients who had diabetes or chronic kidney disease plus uncontrolled hypertension and for 78% of 66,337 patients who had uncontrolled hypertension without the other two cardiovascular risk factors. If those subgroups were more aggressively treated with three or more antihypertensives, the prevalence of truly treatment-resistant hypertension might be closer to 20%-30%, estimated Dr. Egan, professor of medicine and director of the Hypertension Initiative at the Medical University of South Carolina, Charleston.
The findings have significant implications as the U.S. population becomes older and more obese with more complex medical histories and more kidney disease. Practical clinical trials are needed to address the contributors to uncontrolled hypertension, such as therapeutic inertia and the limited effectiveness of current antihypertensive drug regimens, Dr. Egan suggested.
He and his associates analyzed observational data collected from the electronic medical records of more than 150 community-based practices in the multistate Hypertension Initiative.
Resistant hypertension is defined as having a blood pressure above goal while on a regimen of three or more antihypertensive medications, or having controlled blood pressure while on four or more antihypertensives. Pseudoresistance to treatment can result from patients not taking prescribed medications, inaccurate blood pressure measurement, white-coat hypertension, or inadequate therapy. The current study could assess only the medications prescribed, not whether patients adhered to therapy.
Blood pressure goals for hypertensive patients without diabetes or chronic kidney disease were less than 140/90 mm Hg. Blood pressure goals for hypertensive patients with diabetes or chronic kidney disease were less than 130/80 mm Hg.
Blood pressure was uncontrolled in 36% of patients without diabetes or kidney disease and in 60% of patients with those diseases. African Americans were more likely than were whites to have uncontrolled hypertension.
Physicians were more aggressive in treating hypertension in patients with diabetes or kidney disease, prescribing three or more antihypertensives in 35% of patients who achieved goal and 39% of those who did not. Among patients without diabetes or kidney disease, 17% who achieved goal and 22% who did not reach goal received three or more drugs.
Still, that left large numbers of patients who were given two or fewer medications, Dr. Egan noted. No antihypertensives at all were prescribed for 13%-15% of hypertensive patients with diabetes or kidney disease and for 26%-32% without diabetes or kidney disease.
Dr. Egan has had financial relationships with several makers of antihypertensive medications.
No medications were prescribed for 26%-32% of hypertensive patients without diabetes or kidney disease.
Source DR. EGAN