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Blacks and Hispanics who are hypertensive may not be receiving adequate diuretic treatment, two studies indicated.

In the first study, which included black patients with uncontrolled hypertension, only 46% of them were prescribed a diuretic, according to Linda M. Gerber, PhD, of Weill Cornell Medical College in New York City, and colleagues.

Breaking down the data further revealed diuretics were prescribed in fewer than half of those taking one or two antihypertensive drugs," they wrote in the February issue of the American Journal of Hypertension.

In patients taking three or more drugs, nearly one-quarter (21.5%) were not taking a diuretic.

This indicates that the "diuretics are not being chosen as the first- or second-line treatment for the majority of patients," they wrote.

The investigators noted that the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC7) recommends diuretics as the first-line agent in people with hypertension.

"These findings are particularly striking, because all of the patients assessed in this study were black and had uncontrolled hypertension, in whom a diuretic would almost always be recommended," the authors noted.

"The finding is even more disturbing given the socioeconomic status of most patients in this study and the low cost of diuretic therapy that could enhance patient adherence," they added.

To better understand diuretic prescribing patterns in this population, Gerber and colleagues included 658 black patients receiving home care from a large urban home health organization setting. They collected data from records, took three blood pressure readings at a single point in time, and conducted an in-home interview, which included directly recording information from prescription bottles and medication lists.

Two-thirds of the patients were women and patients ranged in age from 21 to 80, with more than half (54%) being 65 or older. Forty-three percent were Medicaid enrollees.

They found that those who were not taking a diuretic also took significantly fewer antihypertensive drugs (1.7 versus 2.9), had significantly higher diastolic blood pressure (89 versus 85 mmHg), and were significantly more likely to have a systolic reading ≥160 mmHg (58% versus 49%, P=0.04).

The systolic blood pressure of those not prescribed a diuretic was a mean 5 mmHg higher compared with patients on diuretics, while diastolic BP was a mean 4 mm higher.

Reasons for these disparities may include unenforceable guidelines or concern about side effects, Gerber told 麻豆传媒.

"We don't think these reasons explain the vast underuse of these medications," Gerber said. "Part of the reason could also be due to a perception that the newer blood pressure drugs are better and they are promoted more aggressively."

A limitation of the study is that results may not pertain to other ethnic groups; however its strength is its focus on an undertreated, understudied population, researchers wrote. Also, the medication information and the blood pressure readings were collected at a single time point.

Hypertension and Dialysis

In the second study, blacks, Hispanics, and other ethnic minority patients with hypertension and on dialysis were about 25% less likely to have "exposure" to each of four common classes of blood pressure medications such as beta-blockers and calcium-channel blockers compared with whites, reported Theresa I. Shireman, PhD, of the University of Kansas School of Medicine in Kansas City, Kans., and colleagues.

Researchers used the term "exposure" because they could not determine the use or adherence to medication. Their analysis spans a mean of 2 years of patient data analysis and was published in the February issue of the American Journal of Hypertension.

For the study, Shireman and colleagues reviewed the records of 38,381 hypertensive patients who began dialysis between January 2000 and December 2005 and who survived at least 90 days after initiation of dialysis. To amass a sizable amount of data, researchers linked the U.S. Renal Data System, which includes Medicare claims, with Medicaid prescription claims data.

"Chronic dialysis patients who have dual eligibility for Medicare and Medicaid, and who are therefore indigent, constitute a uniquely informative population in which to study how prescribing patterns vary by race," they wrote.

Compared with whites, researchers found that African Americans were associated with significantly less exposure to beta-blockers (adjusted OR 0.69) and calcium-channel blockers (adjusted OR 0.85, P<0.0001 for each). The adjusted odds ratios for Hispanics were 0.56 for beta-blockers and 0.84 for calcium-channel blockers (P<0.0001 for each).

Regarding the use of angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs), blacks were 22% less likely to be exposed to this class of drugs, while Hispanics had a 27% less likelihood of exposure (P<0.0001 for each) compared with whites.

They found that the chances of blacks or Hispanics having exposure to one or more blood pressure medications were 22% and 32%, respectively (both P<0.0001), compared with whites.

In addition to reduced odds of even being exposed to the drugs in the first place, once they were prescribed one or more drugs, their cumulative exposure to those drugs was only 70%.

Shireman noted in an interview with 麻豆传媒 that physicians could have discontinued the drug or switched from one medication to another, which would skew the results less favorably toward patients. Another reason for the reduced use of drugs could also be that the dialysis helped to control patients' blood pressure, foregoing the need for drugs.

"Ultimately, we are trying to determine if these drugs are effective in dialysis patients because there is evidence to suggest they are not," she said.

The next leg of the group's research involves examining morbidity and mortality in this patient population, Shireman said.

The study was limited because the results are most likely not applicable to the general population considering the number of Medicaid patients, investigators wrote. Also, they could not prove medication use or disuse, and less medication for minorities could have been a reflection of decreases in hypertension.

From the American Heart Association:

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