Race and Ethnicity in Trials of Antihypertensive Therapy to Prevent Cardiovascular Outcomes: A Systematic Review

Ina U. Park; Anne L. Taylor

doi:10.1370/afm.708

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Figure 1.
Flow diagram of systematic literature search and assessment.
BP = blood pressure; CVD = cardiovascular disease; RCT = randomized controlled trial.
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Figure 2.
Effect of treatment strategies on cardiovascular outcomes in racial/ethnic subgroups.
*Exact 95% CI not provided; range extrapolated from article figure.
ACE = antiotensin-converting enzyme; BP = blood pressure; CHD = coronary heart disease; CI = confidence interval; CV = cardiovascular; CVA = cerebrovascular accident; CVD = cardiovascular disease; HCTZ = hydrochlorothiazide; MI = myocardial infarction; RR = relative risk.

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Table 1.

Trials of Antihypertensive Agents With Cardiovascular Morbidity and Mortality Outcomes

Trial, year	Racial Subgroups No. (%)	Study Sites	Drug Intervention	Follow-up Mean, y	Inclusion Criteria	Subgroups Compared	Baseline Differences (vs Whites)
ACE = angiotensin-converting enzyme; ASA = acetylsalicylic acid; BMI = body mass index; CAD/CHD = coronary artery (heart) disease; CKD = chronic kidney disease; CV = cardiovascular; CVA = cerebrovascular accident; CVD = cardiovascular disease; DM = diabetes mellitus; HTN = hypertension; LVH = left ventricular hypertrophy; TIA = transient ischemic attack.
Characteristics of studies with racial outcome data
ALLHAT,²⁸^–³¹ 2002	White 19,977 (47)  Black 15,085 (35.5)  Hispanic 5,299 (12.5)  Other 2,058 (5)	USA, Canada	Chlorthalidone vs doxazosin, amlodipine, or lisinopril	4.9	Aged >55 y, HTN, prior CAD, or 1 risk factor	Blacks, nonblacks	Blacks: age, baseline CVD, DM, LVH (P<.001)
INVEST,³²^,³³ 2003	White 10,925 (48.3)  Black 3,029 (13.4)  Asian 149 (0.8)  Hispanic 8,045 (35.6) Other 428 (1.9)	North & Latin America, Europe	Verapamil-based vs atenolol-based	2.7	Aged >50 y, HTN, known CAD	Blacks, Hispanics, white, other	Hispanic & black: age, DM, ASA/statin use (P<.001)  Blacks: LVH, BMI, CKD (P<.001)
PROGRESS,³⁴^,³⁵ 2001	White 3,770 (62)  Asian 2,335 (38)	Europe, China, Japan	Perindopril ± indapamide vs placebo	3.9	No age limits, previous CVA or TIA ± HTN	Asians, westerners
VALUE,³⁶^–³⁸ 2004	White 13,643 (89.1)  Black 658 (4.3)  Asian 535 (3.5)  Other 474 (3.1)	USA, Western Europe	Valsartan-based vs amlodipine-based	4.2	Aged >50 y, HTN, 2-3 CV risk factors	Asian, blacks, white, other
LIFE,³⁹^–⁴¹ 2002	White 8,503 (92)  Black 533 (6)  Asian 43 (1)  Hispanic 100 (1)	Europe, USA	Losartan vs atenolol	4.8	Aged 55-80 y, HTN, LVH	Blacks, nonblacks	Blacks: age, DM, CKD, smoking (P <.001)
Studies In single racial/ethnic group
NICS-EH⁴²	Asian 414 (100)	Japan, multiple centers	Nicardipine vs trichlormethiazide	5.0	Aged >60 y, HTN, no prior CVD
JMIC,⁴³ 2004	Asian 1,650 (100)	Japan, multiple centers	Nifedipine vs ACE inhibitors (varied types)	3.0	Aged <75 y, HTN, known
FEVER,⁴⁴ 2005	Asian 9,711 (100)	China, multiple centers	Hydrochlorothiazide + feldopine vs hydrochlorothiazide + placebo	3.3	Aged 50-79 y, HTN, 2 CV risk factors

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The Article in Brief

Race and Ethnicity in Trials of Antihypertensive Therapy to Prevent Cardiovascular Outcomes: A Systematic Review

Ina U. Park, MD , and colleagues

Background Racial and ethnic minority communities have high rates of hypertension (high blood pressure). Racial or ethnic differences in response to drugs intended to lower blood pressure may contribute to differences in cardiovascular disease or high blood pressure between racial or ethnic minorities and whites. This study examines previous research to (1) identify racial differences in the effectiveness of drugs to lower high blood pressure and (2) determine the number and proportion of Asians, blacks, Hispanics, and Native Americans participating in previous research studies.

What This Study Found Of the 28 studies examined, 8 reported results by racial subgroup, and 5 made comparisons between ethnic groups. Four of these 5 studies found similar effectiveness of treatment in whites and minorities.

Implications

Certain groups (such as Native Americans) have high rates of cardiovascular disease but have not been represented in research studies in sufficient numbers to conduct meaningful subgroup analyses.
Including minorities in research studies and analyzing data according to race are important steps in identifying differences in disease course and treatment response--differences that may lead to a reduction in health care disparities in cardiovascular disease.