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Abstract

  1. Top of page
  2. Abstract
  3. METHODS
  4. Study Population
  5. Data Collection Procedures
  6. Statistical Analyses
  7. RESULTS
  8. DISCUSSION
  9. References

In 1997, national recommendations for the treatment of hypertension were made in the form of the Sixth Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC VI). African American hypertensives are considered a special population with a higher prevalence of hypertension, and therefore, unique treatment needs. The study objective was to review medication use among an African American and Latino urban population in relation to the JNC recommendations. The study population was drawn from a preexisting cohort of African Americans and Latinos. Records were reviewed for self-description of hypertension and the use of any antihypertensive medication in individuals less than 60 years of age. A small subgroup of individuals was separately reviewed for specific medications used to treat hypertension. There were 34,118 individuals in the cohort greater than 45 years of age and less than 60 years of age that qualified for review; 40% were African American and 60% were Latino. Of the 13,593 African Americans, 6387 (47%) were hypertensive. Of the 20,525 Latinos, 29% were hypertensive. Only 56% of all hypertensives were on some blood pressure medication (61 % of the African Americans and 48% of the Latinos). Within the subgroup of 550 individuals with detailed medication information (223 African Americans and 327 Latinos), calcium channel blockers and diuretics were the most frequently used medication among the African Americans and angiotensin-converting enzyme inhibitors were the most frequently used medication among the Latinos. Beta blockers were used only 13% of the time. The authors concluded that in this cohort of hypertensive urban Latinos and African Americans, more than 40% of individuals were not being treated for hypertension and, despite the guidelines suggested in JNC VI, few individuals were being treated for their hypertension with diuretic monotherapy or β blockers as first-choice drugs. Instead there was extensive use of calcium channel blockers and angiotensin-converting enzyme inhibitors.

The Sixth Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC VI) report, released in 1997,1 recommends a specific strategy for the treatment of hypertension in the United States. These recommendations are based on outcome trials such as the Systolic Hypertension in the Elderly Program (SHEP)2 and Treatment of Mild Hypertension Study (TOMHS)3 where morbidity/mortality outcomes after the various therapies or placebo are compared. Like its predecessor JNC V, while JNC VI advocates tailoring therapies to meet the needs of special populations, a consistent recommendation was the use of diuretics and β blockers as first-choice agents for the treatment of hypertension in uncomplicated patients. This was due in part to the large number of outcome trials dating from 1966–1996 that utilized diuretics, sympathoplegics, and β receptor blockers. In cases of special populations, such as African Americans, children, the elderly, and pregnant women, the panel made mention of additional therapies that may benefit each specific group.

African Americans have a higher prevalence of hypertension than their Caucasian counterparts. This high blood pressure develops earlier in life and is associated with higher cardiovascular mortality rates.4–6 The well documented decline in cardiovascular mortality that has been seen in Caucasians since the 1970s has not been nearly as striking in minority, and specifically African American, populations.7 The reason for this divergence is unclear and has been attributed by various authors to socioeconomic status, racial stress, or increased genetic susceptibility.4,8–10

First-line therapy for the treatment of hypertension in African Americans as recommended by JNC VI includes diuretics or a low-dose combination of a diuretic and β blocker. Calcium channel antagonists are an acceptable alternative when added to previously existing diuretic monotherapy.

Although no specific JNC VI guidelines address the Latino population, the prevalence of hypertension in this group has been shown to be the same as or lower than that of their Caucasian counterparts.11 Similarly, lower rates of cardiovascular mortality have been noted among Latinos.4 In this study, the treatment of hypertension is examined comparing the medications being used by a group of African American hypertensives and a similar group of Latinos to assess the impact of the JNC VI recommendations on physician prescribing practices for these urban populations.

Study Population

  1. Top of page
  2. Abstract
  3. METHODS
  4. Study Population
  5. Data Collection Procedures
  6. Statistical Analyses
  7. RESULTS
  8. DISCUSSION
  9. References

In 1993, a population-based cohort study among African American and Latino adults aged 45–74 years was initiated in Los Angeles County. A comparison cohort of Japanese and whites was concurrently initiated in Hawaii. The cohort was accessed primarily from driver's license files and the current cohort size is approximately 215,251 including 12,851 African American men; 22,251 African American women; 22,818 Latino men; and 24,620 Latino women. This multiethnic cohort (MEC) is broadly representative of the source populations in the two locations and is described more fully elsewhere.12

The initial mailing to the MEC consisted of a 26-page questionnaire that collected information on diet, prior history of specific medical conditions, including hypertension, diabetes mellitus, myocardial infarction (MI) or stroke, and the use of vitamins and selected drugs. The questionnaire also specifically asked about the use of diuretics, and other antihypertensive medication use.

In 1996, a random sample of the cohort population was generated, and these individuals were contacted and asked to provide blood samples. Biological specimens (blood and urine) are being collected on an ongoing basis from this random sample of the multiethnic cohort. At the time of this specimen collection the phlebotomist administers a follow-up questionnaire. Specific information about individual daily medication use, dosage, and frequency is collected.

Data Collection Procedures

  1. Top of page
  2. Abstract
  3. METHODS
  4. Study Population
  5. Data Collection Procedures
  6. Statistical Analyses
  7. RESULTS
  8. DISCUSSION
  9. References

Cohort African American and Latino individuals, with an age greater than 45 years and less than 60 years at enrollment, were included in the review. The age of 60 was chosen in an effort to identify those individuals most likely to be suffering from primary hypertension rather than secondary hypertension.

The presence of self-described hypertension, the comorbidities present in the different populations, and the frequency of the use of broad classes of antihypertensive medications were abstracted from the initial questionnaire. Specific medication use was obtained on a subgroup of this larger initial population by abstracting data from the follow-up questionnaires administered from 1996–2000.

Statistical Analyses

  1. Top of page
  2. Abstract
  3. METHODS
  4. Study Population
  5. Data Collection Procedures
  6. Statistical Analyses
  7. RESULTS
  8. DISCUSSION
  9. References

Data on medication usage were managed using the SAS statistical software package version 6.11 (SAS Institute, Cary, NC). Descriptive analyses and univariate analyses were performed using the Epilog software package (Epicenter Software, Pasadena, CA). Differences in the prevalence of comorbidities between ethnic groups were evaluated using a χ2 test for homogeneity. For all analyses, the two-tailed level of significance was defined to be α=0.05.

RESULTS

  1. Top of page
  2. Abstract
  3. METHODS
  4. Study Population
  5. Data Collection Procedures
  6. Statistical Analyses
  7. RESULTS
  8. DISCUSSION
  9. References

There were 32,539 individuals in the MEC who were eligible for inclusion in this study (i.e., less than the age of 60 years at entry into the cohort); 13,185 were African Americans and 19,354 were Latinos. The self-reported blood pressure medication use among these individuals is shown in Table I. Hypertensive individuals were on some type of antihypertensive therapy 55% of the time (African Americans 61% and Latinos 48%). In addition, another 19% of these hypertensive individuals, although not on current therapy, had been on some antihypertensive medication in the past. Among the African American hypertensives, almost 69% were using diuretics, compared to 54% of the Latinos.

Table I.  Blood Pressure Medication Usage Patterns Among Individuals Less Than 60 Years Participating in the Multiethnic Cohort: Number of Participants (Column Percent in Parentheses)
Group CharacteristicsTherapeutic CategoryAfrican American, No. (%) (Ncohort=13,185)Latino, No. (%) (Ncohort =19,354)Total, No. (%) (Ncohort =32,539)
Overall
 Total hypertensive6240 (100.0%)5645 (100.0%)11,885 (100.0%)
 Current users3915 (62.7%)2824 (50.0%)6739 (56.7%)
 Past users1055 (16.9%)1638 (29.0%)2693 (22.7%)
 Never users1270 (20.4%)1183 (21.0%)2453 (20.6%)
Current users No. (% current users)No. (% current users)No. (% current users)
 Diuretic*2681 (68.5%)1519 (53.7%)4200 (62.3%)
 Other blood pressure medication**2481 (63.4%)1974 (69.9%)4455 (66.1%)
 Diuretic and other1253 (32.0%)683 (24.2%)1936 (28.7%)
Past users No. (% past users)No. (% past users)No. (% past users)
 Diuretic*979 (92.7%)739 (45.1%)1718 (63.8%)
 Other blood pressure medication**595 (56.4%)633 (38.6%)1228 (45.6%)
 Diuretic and other378 (35.8%)292 (17.8%)670 (24.9%)
*Diuretics in any combination. Includes Diuril, Hydrodiuril, Dyazide, or other; **other blood pressure medications in any combination

The comorbidities by race are listed in Table II. In this cohort, Latinos report an excess of diabetes among those <60 years of age as compared to African Americans (12.4% vs. 11.6%; p=0.0251). This slight elevation is made statistically significant due to the large sample size. Reported MI is more frequent among African Americans as compared to Latinos (7.9% vs. 6.1%) and is highly statistically significant (p<0.0001). Finally, reported stroke is similarly significantly elevated among African Americans compared to Latinos (2.2% vs. 1.2%; p<0.0001).

Table II.  Comorbidities Within the Multiethnic Cohort Members Less Than 60 Years of Age
Diabetes by Ethnicity
EthnicityReported diabetesNo reported diabetesTotal
  African American1531 (11.6%)1165413185
  Latino2407 (12.4%)1694719354
Chi-square for heterogeneity: 5.018; p=0.0251
Myocardial Infarction (MI) by Ethnicity
EthnicityReported MINo reported MITotal
  African American1037 (7.9%)1214813185
  Latino1189 (6.1%)1816519354
Chi-square for heterogeneity: 36.47; p<0.0001
Stroke by Ethnicity
EthnicityReported strokeNo reported strokeTotal
  African American289 (2.2%)1289613185
  Latino235 (1.2%)1911019354
Chi-square for heterogeneity: 47.31; p<0.0001

There were a total of 550 individuals who had completed the detailed follow-up questionnaire and met the criteria for inclusion into this study cohort. Of these, 223 (40%) were African American and 327 (60%) were Latino, reflecting the same distribution as in the cohort as a whole (Table III).

Table III.  Self-Reported Medications by Use by Race and Hypertensive Status
 African AmericanLatino
 HypertensionNo HypertensionHypertensionNo Hypertension
Number9612792235
  AT II antagonists0021
  ACE inhibitors216238
  Antiadrenergics12231
  Antidysrhythmics3212
  Antihyperlipidemics114116
  Antiplatelet1155
  Beta blockers124125
  CCBs336223
  Diuretics336165
  Nitrates4000
  Total130319536
AT II=angiotensin II; ACE=angiotensin-converting enzyme; CCB=calcium channel blocker

Among those reporting hypertension, African Americans more often received polydrug therapy (1.4 medications per individual) as compared to the Latinos (1.0 medications per individual) (Table III). The medications most often used in the African Americans were the calcium channel blockers (CCBs) (33 of the 96 hypertensive individuals [34%]) and angiotensin-converting enzyme (ACE) inhibitors (22%). This was similar to the Latinos who were most frequently prescribed the ACE inhibitors (25%), followed by CCBs (24%). Beta blockers, the medication suggested by JNC VI as first-line agents, were used 13% of the time in African Americans and 13% in Latinos.

Interestingly, the antiadrenergic medications were prescribed for African Americans three times more than in Latinos, a fact that may reflect the higher rate of prostate disease among African Americans.

Men and women also differed with regard to the types of medications prescribed to treat their hypertension. Female hypertensives were treated with CCBs a third of the time while male hypertensives were more frequently treated with diuretics and anti-adrenergic medications (Table IV).

Table IV.  Self-Reported Medications by Use by Gender and Hypertensive Status
 MenWomen
 HypertensionNo HypertensionHypertensionNo Hypertension
Number86143102219
  AT II antagonists0021
  ACE inhibitors206248
  Antiadrenergics13221
  Antidysrhythmics1232
  Antihyperlipidemics16664
  Antiplatelet6501
  Beta blockers97152
  CCBs212347
  Diuretics256235
  Nitrates4000
  Total1153610931
AT II=angiotensin II; ACE=angiotensin-converting enzyme; CCB=calcium channel blocker

Self-reporting of hypertension appears fairly accurate, as only 5% of those calling themselves normotensive were actually taking antihypertensive medications.

DISCUSSION

  1. Top of page
  2. Abstract
  3. METHODS
  4. Study Population
  5. Data Collection Procedures
  6. Statistical Analyses
  7. RESULTS
  8. DISCUSSION
  9. References

The percentage of African Americans and Latino hypertensives in this cohort, 47% and 29% respectively, are similar to the findings of the most recent third National Health and Nutrition Examination Survey (NHANES III) analysis.11 National recommendations suggest that diuretics be the agents of first choice when treating this hypertension. For African Americans, a special ethnic group in terms of cardiovascular risk, CCBs may be added to diuretics as additional therapy. The JNC VI has no specific recommendations for Latinos.

The recommendation of JNC VI and others13 is the use of diuretics in the initial treatment of uncomplicated hypertension. In this MEC, 43% of the African Americans were on diuretic monotherapy while a further 20% were on combination therapy including a diuretic. In the Latinos, 27% were on monotherapy with diuretics and 12% on combination therapy that included a diuretic. Although effective in both African Americans and Caucasians, diuretics, especially low-dose thiazides, may be especially useful as therapy in the former due to their increased salt sensitivity and low renin activity. While these medications do increase cholesterol and glucose levels over the short term, patients taking thiazide diuretics do not appear to be at greater risk for the development of diabetes.14

In this cohort, African Americans were most often treated with diuretics, CCBs, and ACE inhibitors. ACE inhibitors appear to be an effective adjunct to diuretic therapy in African Americans due to both the enhanced blood pressure lowering of that combination, and to the decreased production of angiotensin II.15 It appears that the ACE inhibitors may also have beneficial effects on the progression of hypertensive renal disease, especially when compared to some of the shorter-acting CCBs.16 Given the disproportionately high incidence of renal failure among African Americans, and the importance of hypertension in the etiology of this renal disease, the regimen of an ACE inhibitor and diuretic in combination seems appropriate.17

In other clinical situations, such as chronic heart failure, ACE inhibitors may not be the best medication for African Americans. A recently reported trial18 described a lack of efficacy of enalapril in African Americans with left ventricular dysfunction as compared to similar whites when the end point of death or hospitalization for congestive heart failure was used. For these patients, a nonselective β blocker with α-adrenergic antagonism activity, such as carvedilol or labetalol, has been suggested as possible therapy.19

The hypertensives among the Latinos were treated primarily with ACE inhibitors and CCBs. The choice of ACE inhibitors in this ethnic group is supported by several recent trial outcomes that have been published or presented since the publication of JNC VI. The Heart Outcomes Prevention Evaluation (HOPE)20 demonstrated the benefit of ACE inhibitors in reducing the morbidity and mortality secondary to cardiovascular disease among diabetics. The Swedish Trial in Old Patients with Hypertension-2 (STOP-2) investigators21 showed that ACE inhibitors were similar to conventional therapy and to CCBs in the reduction of congestive heart failure and MIs in the elderly.

Monotherapy with ACE inhibitors is recommended as therapy in the setting of specific comorbidities such as diabetes mellitus type 1 and in post-MI patients who are experiencing systolic dysfunction.1 Interestingly, among those individuals on monotherapy in the group under study here, almost one half of the Latino individuals (a population with a high diabetes burden) were on ACE inhibitors.22 Overall though, therapy with a single agent probably does not allow achievement of lower target blood pressures with the least amount of side effects.

Alpha blockers are effective in reducing peripheral vascular resistance and therefore decreasing hypertension. They appear to have their greatest effects in the presence of a diuretic. They are also indicated for the noninvasive treatment for the symptoms of benign prostatic hypertrophy, which might appear to make them an attractive choice as a first-line antihypertensive medication in a select subgroup of male patients.23,24 Although used relatively frequently in this cohort, the recent findings of the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT)25 demand a re-evaluation of the use of these agents in hypertensive patients. Preliminary results have led to the removal of study patients from the α-blocker treatment arm due to an increase in congestive heart failure, stroke, and coronary revascularization.25

Another finding in this population of individuals less than 60 years of age was the relative lack of therapy for those self-described as hypertensive. Only 61% of the hypertensive African Americans were currently on therapy, while 19% had been on therapy and had stopped. Twenty percent of the individuals that identified themselves as hypertensive have apparently never been on medical therapy. Given the increased severity of hypertensive disease among African Americans and the higher rates of stroke, renal disease, and cardiac disease seen in this population (Table II), this large group of untreated individuals (39% of the hypertensives) appear at risk for increased long-term morbidity and mortality.1

The Latinos in the cohort, while generally thought of as having lower blood pressure as a group, were not on therapy for their hypertension almost 50% of the time. This places this group with its low cardiovascular disease burden at higher risk for target organ damage.

Given the degree of cardiovascular risk associated with hypertension and the documented increase in sudden death, especially among African Americans, another emphasis of care givers should be on eliminating any additional cardiovascular risk factors. However, regardless of the individual medications being used to treat hypertension in these populations, the use of antihyperlipidemic medications for both African Americans and Latinos was 19% in men and 6% in women. As has been previously reported,26 both populations in this cohort have relatively high body mass indices, which is typically associated with abnormal lipid profiles, making the use of antilipid agents appropriate in the prevention of cardiovascular disease.

A potential limitation in this review includes the use of a self-described cohort of hypertensive patients. For the most part, those that described themselves as being normotensive were not taking medications for hypertension (97%). In addition, this review only included individuals less than 60 years of age in order to focus on those individuals whose disease process most likely reflected primary hypertension. Another limitation is that the review includes some individuals who had secondary questionnaire data obtained immediately before, as well as simultaneously with the release of JNC VI in 1997. It should be noted, however, that the recommendations of JNC V were similar with regard to the initial use of diuretics and β blockers as suggested initial therapy, in contrast to our findings.27 Finally, due to the relatively small number of individuals studied, we could not investigate the relationship between the presence of diabetes, previous stroke or MI, and reported antihypertensive therapy.

The antihypertension medications used by the individuals in this cohort do not closely correspond to the published national guidelines. Some of the therapeutic changes (e.g., the use of ACE inhibitors) seen among this group are consistent with information published subsequent to the JNC VI guidelines. More noteworthy, however, are the high numbers of self-reported hypertensive individuals in both urban populations who are not currently on therapy.

Acknowledgment: Acknowledgment: This project was supported in part by grant NIH U01 CA 63464.

References

  1. Top of page
  2. Abstract
  3. METHODS
  4. Study Population
  5. Data Collection Procedures
  6. Statistical Analyses
  7. RESULTS
  8. DISCUSSION
  9. References
  • 1
    The sixth report of the Joint National Committee on prevention, detection, evaluation, and treatment of high blood pressure. Arch Intern Med. 1997;157:24132445.
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    Exner DV, Dries DL, Domanski MJ, et al. Lesser response to angiotensin-converting-enzyme inhibitor therapy in black as compared to white patients with left ventricular dysfunction. N Engl J Med. 2001;344:13511357.
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    Yancy CW, Fowler MB, Colucci WS, et al. Race and the response to adrenergic blockade with carvedilol in patients with chronic heart failure. N Engl J Med. 2001;344:13581365.
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    Yusuf S, Sleight P, Pogue J, et al. Effects of an angiotensin-converting-enzyme inhibitor, ramipril, on cardiovascular events in high risk patients. The Heart Outcomes Prevention Evaluation Study Investigators. N Engl J Med. 2000;342;145153. 2.
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    Hansson L, Lindholm LH, Ekbom T, et al. Randomized trial of old and new antihypertensive drugs in elderly patients: cardiovascular mortality and morbidity in the Swedish Trial in Old Patients with Hypertension-2 study. Lancet. 1999;354: 17511756.
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    Norris SL, de Guzman M, Sobel E, et al. Risk factors and mortality among black, Caucasian and Latina women with acute myocardial infarction. Am Heart J. 1993;126:13121319.
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    Roehrborn CG, Oesterling JE, Auerbach S, et al. The Hytrin Community Assessment Trial study: a one-year study of terazosin versus placebo in the treatment of men with symptomatic benign prostatic hyperplasia. HYCAT Investigator Group. Urology. 1996;47:159168.
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    Lowe FC, Olson PJ, Padley RJ. Effects of terazosin therapy on blood pressure in men with benign prostatic hyperplasia concurrently treated with other antihypertensive medications. Urology. 1999;54:8185.
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    ALLHAT Collaborative Research Group. Major cardiovascular events in hypertensive patients randomized to doxazosin vs. chlorthalidone: the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) JAMA. 2000;283:19671975.
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    Henderson SO, Bretsky P, Henderson BE, et al. Risk factors for cardiovascular and cerebrovascular death among African Americans and Hispanics in Los Angeles, California. Acad Emerg Med. 2001;8:11631172.
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    The fifth report of the Joint National Committee on detection, evaluation, and treatment of high blood pressure (JNC V). Arch Intern Med. 1993;153:154183.