Hypertension Detection And Follow-up Program Research Articles

Thirty-year survival for black and white hypertensive individuals in the Evans County Heart Study and the Hypertension Detection and Follow-up Program

The Evans County Heart Study (ECHS), initiated in 1960, was one of the first major studies to document cardiovascular disease (CVD) risks for African Americans and Caucasians with elevated blood pressures. In the early 1970s, the Hypertension Detection and Follow-up Program (HDFP), with a site in Georgia (HDFP-GA), was one of the first major studies to demonstrate that treating hypertension with stepped care (SC), vs. referred care (RC), has better short-term outcomes. With this background, study objectives were to evaluate 30-year survival and cardiovascular outcomes of the HDFP-GA and to compare outcomes of these patients with 1,619 hypertensive individuals (30 to 69 years of age) from the ECHS. The HDFP-GA patients included 688 individuals (Black [n = 267]; White [n = 421]) randomized to RC (n = 341) and SC (n = 347). The ECHS was comprised of 733 Black and 886 White hypertensives. All-cause mortality and CVD mortality were assessed in the HDFP-GA and compared with those in the ECHS hypertensives. After 30 years of follow-up, 65.7% of the HDFP-GA cohort had died compared with a similar 65.8% of the ECHS hypertensives. However, CVD mortality rates, while similar for the SC and RC arms, were lower than in the HDFP-GA total study group than the hypertensive participants of ECHS (32.6% vs. 40.3%; P < .001). CVD survival rates for both SC and RC HDFP-GA arms were significantly better than population-based hypertensive individuals in the ECHS, with consistent benefits in all four race-gender groups. These results identify the importance of long-term follow-up of individuals in hypertension studies and trials that include CVD outcomes.

Getting to Goal Blood Pressure: Why Reserpine Deserves a Second Look

Getting to Goal Blood Pressure: Why Reserpine Deserves a Second Look

Obesity and Prevalent and Incident CKD: The Hypertension Detection and Follow-Up Program

Obesity is associated with increased single-nephron glomerular filtration rate, which may increase the risk for chronic kidney disease (CKD), especially when combined with hypertension. However, epidemiological data supporting an association between overweight and obesity and risk for CKD currently are limited. We used data from the Hypertension Detection and Follow-Up Program (HDFP) to test the hypothesis that overweight and obesity are associated with incident CKD in 5,897 hypertensive adults. Serum and spot urine samples were collected at baseline and year 5. CKD is defined as the presence of 1+ or greater proteinuria on routine urinalysis and/or an estimated glomerular filtration rate less than 60 mL/min/1.73 m2 (<1.0 mL/s). In HDFP participants without CKD at baseline, the incidence of CKD at year 5 was 28% in the ideal-body-mass-index group, 31% in the overweight group, and 34% in the obese group. After adjustment for all covariates, including diabetes mellitus, mean baseline diastolic blood pressure, and slope of diastolic blood pressure, both baseline overweight (odds ratio [OR], 1.21; 95% confidence interval [CI], 1.05 to 1.41) and obesity (OR, 1.40; 95% CI, 1.20 to 1.63) were associated with increased odds of incident CKD at year 5. Similar results were noted after exclusion of participants with baseline diabetes mellitus, with both overweight (OR, 1.22; 95% CI, 1.05 to 1.43) and obesity (OR, 1.38; 95% CI, 1.17 to 1.63) remaining significantly associated with incident CKD. These results suggest that obese adults with hypertension have an increased risk for CKD.

Clinical Trials in Hypertension

Henry Black, ed. 606 pp. New York: Marcel Dekker; 2001. $225.00. ISBN 0-8247-02700 Large, randomized clinical trials of treatments with blood pressure–lowering drug regimens have a long history that is usually dated from the Veterans Administration (since renamed the Department of Veterans Affairs) (VA) Cooperative Study on Antihypertensive Drugs, which reported results from 1967–1972. This useful book collects in one 660-page volume a good part of that history, including an attempt (in the last 5 chapters) to give a flavor of ongoing activity. In all cases, the chapters are authored by ≥1 of the clinical and/or coordinating center leaders of the particular trial and thus often give insights into the thinking behind the design, conduct, and interpretation, which is otherwise not easily available. The chapters on completed trials also collect in 1 place the information from many separate publications on the methods and results of the trials; eg, upwards of 30 study reports are cited in the Hypertension Detection and Follow-up Program (HDFP) chapter. The book’s organization is approximately chronological, which provides the reader who troubles to start at the beginning the special pleasure of (re)discovering many groundbreaking and still relevant features of …

Current and remote blood pressure and cognitive decline.

Previous studies raise the possibility that blood pressure (BP) in middle age predicts later cognitive decline. To examine prospectively the relationship of BP with level of and change in cognitive function in the elderly. Longitudinal, population-based study comprising subjects enrolled in the East Boston component of the Established Populations for the Epidemiologic Study of the Elderly (EPESE) (1982-1983) and the Hypertension Detection and Follow-Up Program (HDFP) (1973-1974). East Boston, Mass. Of the 3657 participants in the EPESE with baseline BP measurements, 2068 also participated in the HDFP. Subjects were aged 65 to 102 years at baseline in the EPESE and had mental status and memory assessed at baseline and 3 and 6 years. Numbers of errors on the Short Portable Mental Status Questionnaire and the East Boston Memory Test and rates of change in these numbers of errors. Subjects had BP measured both at baseline in the EPESE and 9 years before, as part of the HDFP. In analyses adjusted for age, sex, and education, there was no strong linear association between BP and cognition. The associations found were fairly small in magnitude, and varied according to which test was used to measure cognition. There was little evidence for an effect of BP on change in cognitive function with either test, or for an effect on level of function on the memory test. In analyses of level of mental status questionnaire performance, however, elevated systolic BP (> or =160 mm Hg) 9 years before baseline was associated with a 14% (95% confidence interval [CI], 4%-25%) increase in error rate, relative to the referent (130-139 mm Hg). Baseline systolic BP had a U-shaped association with the number of errors; error rates were 9% higher compared with the referent group among those with systolic BP lower than 130 mm Hg (95% CI, 1%-17%) and 7% greater (95% CI, 0%-15%) among those with elevated systolic BP. Diastolic BP 9 years before baseline also had a U-shaped association with errors on the mental status questionnaire. The findings do not suggest a linear association of BP with cognitive decline, but they are consistent with a more complex relationship between BP and cognition than previously appreciated.

The rationale for differing national recommendations for the treatment of hypertension.

This article examines the rationale for the differences in the guidelines for hypertension management of four national or international bodies: the Joint National Committee (JNC-V), The World Health Organization/International Society of Hypertension (WHO-ISH), the British Hypertension Society (BHS), and the New Zealand guidelines. These guidelines agree on many aspects of management, but differ on two very important points-the drugs of first choice for hypertension, and the indications for drug treatment of uncomplicated mild hypertension. JNC-V recommends treatment routinely of all people with a sustained blood pressure of 140/90 mm Hg, whereas the BHS guidelines advise treatment routinely at 160/100 mm Hg. Such differences in the threshold for treatment have a major impact on the proportion of the adult population to be treated, and on the benefit from treatment. JNC-V was heavily influenced by the Hypertension Detection and Follow-up Program (HDFP), which appeared to show a large benefit from the treatment of uncomplicated mild hypertension, whereas the BHS guidelines were influenced by the Medical Research Council (MRC) Trial, which showed a very small benefit. However, the apparent differences in absolute benefit between these, and other, randomized controlled trials is related entirely to differences in the absolute cardiovascular risk of the populations studied. In populations and in individual patients the benefit from antihypertensive treatment is determined by the absolute cardiovascular risk. Blood pressure by itself is a very weak predictor of risk or benefit from treatment. In uncomplicated mild hypertension the need for drug therapy should be based on the absolute risk of cardiovascular complications, estimated by considering age, sex, serum cholesterol level, diabetes mellitus status, and smoking habits, in addition to blood pressure. Doctors cannot estimate absolute risk accurately informally or intuitively, and the next generation of guidelines should incorporate a simple but accurate method for estimating cardiovascular risk, similar to that in the New Zealand guidelines. The decision to treat, or not treat, uncomplicated mild hypertension should be based on a formal estimate of absolute cardiovascular risk and not on an arbitrary blood pressure threshold. As regards drugs of first choice, the available evidence supports strongly the stance of JNC-V and JNC VI that diuretics and beta-blockers should be preferred unless they are contraindicated, or unless there are positive indications for other drug classes.

Hypertension in the Elderly: Correction and Clarification

To the Editor. —I read with great interest the article by Dr Mulrow and colleagues.1I congratulate both the editors ofJAMAand the authors for bringing the results of this excellent work to the attention of the medical community. There is, however, an error and an oversight in the article. The legend to Figure 11(p1934)indicates that HTN Coop stands for Detection and Follow-up Program Cooperative Yet the reference next to HTN Coop given in the body of Figure 1 is number 3. This is not one of the Hypertension Detection and Follow-up Program (HDFP) articles as they appear in the author's reference list (eg, references 4,31, and 48). Rather, their reference number 3 is an article from the Hypertension-Stroke Cooperative Study Group.2The question is whether the data in Figure 1 represent results from the HDFP or the Hypertension-Stroke Cooperative Study Group. Furthermore, in

Long-term pharmacologic treatment of women with hypertension.

As reviewed in "Hypertension in Women: What is Really Known?" (Women's Caucus Working Group on Women's Health of the Society of General Internal Medicine [1991] Ann Intern Med 115:287-293), the published literature reveals that hypertension frequently occurs in women and that only some prospective studies have defined specific benefits and risks of long-term pharmacologic treatment. Major U.S. epidemiologic studies show the incidence of hypertension to very between 20% and 50% of the population. It is more common among Afro-Americans than White Americans. Frequency increases with aging. Several studies of at least 3 years duration that have focused on the use of diuretics and B blockers are reviewed: Hypertension Detection and Follow-Up Program (HDFP), Medical Research Council (MRC), MRC trial in the treatment of older adults (MRC-Older), and isolated systolic hypertension in the elderly (SHEP). Both diuretics and B blockers generally lower blood pressure, and decrease stroke incidence and mortality. Diuretics seem to be more effective and better tolerated than B blockers. Long-term studies of newer antihypertensive agents do not yet exist. The sexual side effects of drugs have only been studied to a limited degree in women. © 1995 Wiley-Liss, Inc.

Socioeconomic status in the epidemiology and treatment of hypertension.

The association of socioeconomic status (SES), as indexed by educational achievement, with the prevalence, prognosis, and efficacy of treatment of hypertension in the Hypertension Detection and Follow-up Program (HDFP) was reviewed. The prevalence of hypertension varied inversely with SES during the screening program initiated to identify HDFP eligibles in 14 communities in 1973-1974. There was a strong inverse gradient of 5-year all-cause mortality with SES among the hypertensive participants referred to usual care in the HDFP. The association of mortality with SES among hypertensive subjects was eliminated by the HDFP stepped-care program. A large portion of the efficacy of the HDFP was associated with in-trial blood pressure control. Inasmuch as these results are generalizable to the nation, a large fraction of hypertension-associated morbidity and mortality in the United States was related to lower SES in the 1970s, before widespread implementation of programs resulting in increased awareness, treatment, and control of hypertension.

Persistence of reduction in blood pressure and mortality of participants in the Hypertension Detection and Follow-up Program. Hypertension Detection and Follow-up Program Cooperative Group

The Hypertension Detection and Follow-up Program (HDFP) previously described a significant reduction in five-year, all-cause mortality in its intensively treated stepped care (SC) group relative to its referred care (RC) control group. At the time this finding was described, a proportion of the SC cohort had been treated for periods as long as 6.7 years, but comparable RC and SC mortality data beyond five years were not available. These data, which are described herein, indicate that the 6.7-year life-table mortality rates were 95.1/1000 participants for SC vs 116.3/1000 participants for RC, a larger mortality difference than was observed at five years. This favorable finding for SC extended to all major subgroups, including white women and those aged 30 to 49 years at trial entry. Six months after the close of the treatment trial, a two-year posttrial surveillance study, which extended mortality follow-up to 8.3 years, was conducted. The posttrial use of antihypertensive medication declined in SC and increased in RC participants so that by the end of the posttrial period, there was little difference in the percentages of SC and RC participants taking medication. Control of blood pressure, indicated by mean diastolic blood pressure and by percent of participants with a pressure of 90 mm Hg or less, was slightly better for SC than for RC participants (SC group, 86.5 mm Hg and 68% controlled; RC group, 87.8 mm Hg and 62% controlled). The absolute mortality advantage found at 6.7 years persisted and increased throughout the posttrial period of follow-up despite discontinuation of the formal SC therapy program. It is postulated that regression of hypertensive end-organ changes brought about by the more effective SC treatment caused this favorable outcome.

Persistence of Reduction in Blood Pressure and Mortality of Participants in the Hypertension Detection and Follow-up Program

The Hypertension Detection and Follow-up Program (HDFP) previously described a significant reduction in five-year, all-cause mortality in its intensively treated stepped care (SC) group relative to its referred care (RC) control group. At the time this finding was described, a proportion of the SC cohort had been treated for periods as long as 6.7 years, but comparable RC and SC mortality data beyond five years were not available. These data, which are described herein, indicate that the 6.7-year life-table mortality rates were 95.1/1000 participants for SC vs 116.3/1000 participants for RC, a larger mortality difference than was observed at five years. This favorable finding for SC extended to all major subgroups, including white women and those aged 30 to 49 years at trial entry. Six months after the close of the treatment trial, a two-year posttrial surveillance study, which extended mortality follow-up to 8.3 years, was conducted. The posttrial use of antihypertensive medication declined in SC and increased in RC participants so that by the end of the posttrial period, there was little difference in the percentages of SC and RC participants taking medication. Control of blood pressure, indicated by mean diastolic blood pressure and by percent of participants with a pressure of 90 mm Hg or less, was slightly better for SC than for RC participants (SC group, 86.5 mm Hg and 68% controlled; RC group, 87.8 mm Hg and 62% controlled). The absolute mortality advantage found at 6.7 years persisted and increased throughout the posttrial period of follow-up despite discontinuation of the formal SC therapy program. It is postulated that regression of hypertensive end-organ changes brought about by the more effective SC treatment caused this favorable outcome. (<i>JAMA</i>1988;259:2113-2122)

Recruitment in the Hypertension Detection and Follow-up Program

The Hypertension Detection and Follow-up Program (HDFP), through a two-stage population-based screen for high blood pressure involving over 159,000 persons in 14 U.S. communities, recruited and randomized 11,386 participants. The design initially called for the recruitment of 800–1000 hypertensive individuals per clinic over a 9-month period. The size of the population to be screened was based on an estimated 15% of the general population being age and blood pressure (BP) eligible. All adults 30–69 years of age in defined populations were to be screened, with efforts to enroll into the trial all who met the BP eligibity criteria. Recruitment was carried out by interviewers who enumerated households and screened age-eligible individuals for elevated BP; those meeting BP criteria were invited to a clinic screen for confirmation. Of those persons enumerated, 179,239 were age eligible, and 159,566 of these had home BP measurements. The home screening yielded 22,994 persons who had a diastolic BP at or above 95 mm Hg, and 17,499 attended the clinic screen. At the clinic screen, 11,386 had diastolic BP at or above 90 mm Hg and were randomized into one of two treatment groups. The enumeration goal, and the recruitment yield and cost varied by clinic, primarily due to different characteristics of the defined populations. Overall, the target population approximated U.S. demographic characteristics except that a larger proportion of blacks was included. Because of generally good response rates, the randomized study population was representative of similarly aged hypertensive persons in the target populations. The recruitment results suggest that a population-based screening program for a high prevalence condition such as hypertension is an effective mode of recruitment, particularly when a population-based sample is required.

Standardized physician preparation of death certificates

One method for determining cause of death in a clinical trial is to use standard nosological coding of death certificates. In order to look at an alternative approach, the Hypertension Detection and Follow-up Program (HDFP) assessed underlying causes of death through the use of three physicians. These physicians were trained and standardized in the proper recording of cause of death on death certificates. Each physician completed a death certificate for each of the 768 deaths in the HDFP, utilizing all available information, including HDFP records, plus any additional hospital and autopsy records. The new standardized death certificates were then transmitted to a panel of three nosologists who coded the cause of death. The physician preparation procedure was compared with a procedure wherein a panel of three nosologist coded the original death certificate for the underlying cause of death. The procedures agreed on the three-digit International Classification of Disease, Adapted code in 60.1% of the cases. The agreement rate improved to 72.5% when disease codes were collapsed into broad disease categories utilized in the HDFP.

The association of postural changes in systolic blood pressure and mortality in persons with hypertension: the Hypertension Detection and Follow-up Program experience.

Participants in the Hypertension Detection and Follow-up Program (HDFP) were classified on the basis of baseline standing minus sitting systolic blood pressure into four groups (less than or equal to -20 [group 1], -19 to 0 [group 2], 1 to 20 [group 3], and greater than 20 mm Hg [group 4]) to study 5 year mortality. Group 1, 3.3% of the total, contained those participants who had postural hypotension. The 5 year total and age-adjusted mortality rates for these groups were significantly different (p less than .04), with group 1 having the highest rates. To account for the possible confounding effects of certain baseline risk factors--age, sex, race, prior antihypertensive treatment, randomization group, diabetes, end-organ damage, sitting diastolic and systolic blood pressures, pulse, hematocrit, smoking status, and relative weight (percent of ideal weight)--in assessing group differences in mortality rates, a multiple logistic model was used. Relative weight proved to be a confounding factor for the association of drop in postural systolic blood pressure with mortality. However, there is an interaction between history of diabetes and postural change in systolic blood pressure. Thus, postural hypotension may indicate a poor prognosis in diabetic hypertensive patients.

Incidence of coronary heart disease and left ventricular hypertrophy in the Hypertension Detection and Follow-up Program

NASMUCH AS the primary end point of the Hypertension Detection and Follow-up Program (HDFP) was total mortality (ie, death from all causes), any analysis of the data dealing with cause-specific mortality, such as coronary heart disease, should be reviewed with caution because of the small number of events, especially in subgroups. Nevertheless, coronary heart disease events are important clinical findings of HDFP and deserve attention, especially since end points for both coronary heart disease and left ventricular hypertrophy (LVH) were defined at the beginning of the trial and were considered as secondary HDFP end points. Criteria for their diagnoses and procedures for data collection related to their ascertainment were established beforehand. Further, adherence to these procedures was monitored by the HDFP Coordinating Center. These data were collected as part of the HDFP design, described in the article by Davis et al elsewhere in this issue. METHODS Coronary heart disease (CHD) was defined as any clinical manifestation of ischemic heart disease related to atherosclerosis of the coronary arteries. These included coronary heart disease deaths, possible or probable acute nonfatal myocardial infarction (MI), and angina pectoris (AP) as defined below.

Clinicians' interpretation of the results and implications of the Hypertension Detection and Follow-up Program

I N THE LAST few years, a variety of nonpharmacologic therapies and newer antihypertensive agents have been advocated for longterm treatment of hypertension.‘*2 Proponents of these approaches frequently point to the variable risk of high BP, potential hazards of diureticbased antihypertensive therapy, and the “uncertain” benefit of treating patients with mild hypertension. 3-5 Individualization of treatment based on risk factor analysis, demographic features, hemodynamic characteristics, humoral factors, or volume status have been proposed in the hope of maximizing benefits and minimizing the risks of antihypertensive therapy. These obviously desirable goals have received considerable attention in the recent medical literature and, unfortunately, may overshadow several important observations made during the Hypertension Detection and Follow-up Program (HDFP) trial of Stepped Care (SC) treatment in hypertensive patients.“13 Nearly a decade has passed since the first Joint National Committee (JNC) on Detection, Evaluation, and Treatment of High Blood Pressure published their treatment recommendations.14 At that time, the benefit of drug therapy in middle-aged men with diastolic blood pressures (DBPs) of 105 to 129 mm Hg had been demonstrated during the Veterans Administration trial, but a reduction in coronary heart disease mortality and a favorable effect of drug treatment in patients with mild hypertension were not observed.‘51’6 This prompted the committee to recommend that treatment of patients with DBPs from 90 to 104 mm Hg “should be individualized, with consideration given to other risk factors.” Nonpharmacologic therapies (weight reduction, sodium restriction) were suggested as alternatives to drug treatment in light of the uncertain benefit of pharmacologic theraPYJ4 These recommendations were certainly reasonable at the time, since there was little published information available to document the efficacy of long-term drug treatment in producing a sustained antihypertensive response in ambulatory individuals with mild hypertension. Compliance was viewed as a major obstacle, and rightfully so, since there was concern that potential side effects and the inconvenience of continuous drug treatment would prompt treatment withdrawal in a high percentage of patients. The issues of compliance and toxicity in elderly patients were of major concern, since there was virtually no information about the safety of treatment in these individuals. All of these facts, when combined with the lack of documentation of a beneficial effect of BP reduction by drugs in patients with mild hypertension obviously influenced many physicians to withhold therapy. The pattern of treatment in patients referred to their usual sources of care in the community (Referred Care [RC] group) in the HDFP reflects this viewpoint.6 More recently, potential hazards of diureticbased antihypertensive therapy have been stressed because of the observation from the Multiple Risk Factor Intervention Trial (MRFIT) that aggressively treated men (specialized intervention [Si] group) with mild hypertension and abnormal resting ECGs had an increased coronary heart disease mortality when compared with a similar subset of men receiving care in the community (usual care [UC] group).” Unfortunately, the well-intentioned reviews that stress the lack of a statistically significant reduction in mortality of treated patients with mild hypertension in certain trials and the potential hazard of diuretic-based antihypertensive therapy after target organ involvement has developed as suggested in MRFIT can dissuade clinicians from instituting definitive antihypertensive therapy. Physicians may be per-

The hypertension detection and follow-up program design, methods, and baseline characteristics and blood pressure response of the study population

THE HYPERTENSION Detection and Follow-up Program (HDFP) was a national, multicenter, randomized, 5-year clinical trial of the effectiveness of antihypertensive therapy in reducing all-cause mortality in hypertensive participants screened from the general population. The study was funded under contract by the National Heart, Lung, and Blood Institute (NHLBI). Clinical centers in 14 US communities were selected by competitive contract review to participate in the study. Also selected were a Central Laboratory for standardized determinations of participant biochemical values, an ECG Center for standardized ECG interpretations, and a Coordinating Center for (1) data collection, (2) monitoring and analysis, (3) standardization, staff training, and regulation of study protocol, and (4) overall project coordination.

Cerebrovascular events in the Hypertension Detection and Follow-up Program

T HIS ARTICLE focuses on the 5-year occurrence of fatal and nonfatal stroke in the Hypertension Detection and Follow-up Program (HDFP) Stepped Care (SC) and Referred Care (RC) hypertensive participants. A number of clinical trials of hypertension have reported reductions in fatal and nonfatal stroke in hypertensive patients receiving antihypertensive treatment.‘” This was true in the HDFP also, where the dramatic effect of SC therapy provided by the special hypertension clinics was observed in the reduction of 5-year fatal and nonfatal stroke as compared with RC, where less aggressive antihypertensive treatment was provided by community sources.

Adverse effects of antihypertensive medications in the Hypertension Detection and Follow-up Program

T HE BENEFICIAL effects of drug treatment have been demonstrated in individuals with hypertension.‘-* The adverse effects of antihypertensive medications also have been well documented.9-‘4 While in most individuals high BP can be treated safely, side effects of drugs are relatively frequent and may have notable effects on quality of life and compliance with the prescribed regimens. Although the Hypertension Detection and Follow-up Program (HDFP) was not designed to study the side effects of drugs in comparison with placebo, its Stepped Care (SC) category does constitute the largest cohort (N = 5,485) from which detailed antihypertensive drug surveillance data are available in the United States. The data presented herein represent a description of the experience of the HDFP with antihypertensive drug side effects.

Time trends in the US racial difference in hypertension.

This paper explores time trends in racial differences in hypertension and in mortality from complications from hypertension in the United States. Mortality data were derived from death certificate data compiled by the National Center for Health Statistics and presented in the 1981 Report of the Working Group on Arteriosclerosis. Prevalence data were obtained from five populations--6,672 people screened in 1960-1962 by the National Health Examination Survey (NHES); 20,749 screened in 1971-1975 by the Health and Nutrition Examination Survey (HANES I); 158,539 screened in 1973-1974 by the Hypertension Detection and Followup Program (HDFP); 1 million persons screened in 1973-1975 by the Community Hypertension Evaluation Clinics (CHEC); and 20,325 screened in 1976-1980 by the second Health and Nutrition Examination Survey (HANES II). Mortality data indicate that the nonwhite/white ratios for mortality from complications of hypertension increased between 1940 and 1967 and decreased between 1968 and 1978. Prevalence data show a corresponding recent decrease in black minus white mean blood pressure. Some of the decrease appears to be due to a greater improvement in hypertension control for blacks than for whites. Time trends in the black/white ratio in prevalence of hypertension were examined with differential treatment effects controlled by inclusion as hypertensive those on drug therapy. The results indicate that in addition to differential changes in therapy, the ratio of black/white prevalence of hypertension may also be decreasing. Additional studies are needed to confirm this finding and to explore time changes in racial patterns of risk factors for hypertension.