Regional and racial differences in response to antihypertensive medication use in a randomized controlled trial of men with hypertension in the United States. Department of Veterans Affairs Cooperative Study Group on Antihypertensive Agents.

BACKGROUND: Stroke incidence and mortality rates are higher in the southeastern region of the United States, which is called the "Stroke Belt." We compared the response to antihypertensive medication use in patients from different US regions. METHODS: The short-term and 1-year efficacy of the antihypertensive medications hydrochlorothiazide, atenolol, diltiazem hydrochloride (sustained release), captopril, prazosin hydrochloride, and clonidine was compared by US region in a randomized controlled trial of 1,105 men with hypertension from 15 US Veterans Affairs medical centers. RESULTS: Compared with patients outside the Stroke Belt, patients inside the Stroke Belt achieved significantly lower treatment success rates of diastolic blood pressure control at 1 year with hydrochlorothiazide (63% vs 41%), atenolol (62% vs 46%), captopril (60% vs 30%), and clonidine (69% vs 43%); there were no differences in treatment success rates with diltiazem (70% vs 71%) or prazosin (54% vs 53%). When controlling for race, patients inside the Stroke Belt had significantly lower treatment success rates with hydrochlorothiazide (P = .003) and clonidine (P = .003), and the lower success rate with atenolol approached significance (P = .15). Regardless of region, blacks were less likely than whites to achieve treatment success with atenolol (P = .02) or prazosin (P = .03) and more likely with diltiazem (P = .05). There was a trend for blacks residing inside the Stroke Belt to have a lower treatment success rate than other race-region groups when treated with captopril (P = .07). Many regional and racial differences in diet, lifestyle, and other characteristics were observed. After adjustment for these characteristics by regression analysis, the effect of residing inside the Stroke Belt remained for captopril (P = .01) and clonidine (P = .01) and approached significance for hydrochlorothiazide (P = .10). CONCLUSIONS: Hypertension in patients residing inside the Stroke Belt responded less to the use of several antihypertensive medications and important differences were shown in a number of characteristics that may affect the control of blood pressure, compared with patients residing outside the Stroke Belt.

The role of diastolic blood pressure when treating isolated systolic hypertension.

OBJECTIVE: To assess the role of treated diastolic blood pressure (DBP) level in stroke, coronary heart disease (CHD), and cardiovascular disease (CVD) in patients with isolated systolic hypertension (ISH). DESIGN: An analysis of the 4736 participants in the Systolic Hypertension in the Elderly Program (SHEP) was undertaken. The SHEP was a randomized multicenter double-blind outpatient clinical trial of the impact of treating ISH in men and women aged 60 years and older. MAIN OUTCOME MEASURES: Cox proportional hazards regression analysis, with DBP and systolic blood pressure (SBP) as time-dependent covariables. RESULTS: After adjustment for the baseline risk factors of race (black vs other), sex, use of antihypertensive medication before the study, a composite variable (diabetes, previous heart attack, or stroke), age, and smoking history (ever vs never) and adjustment for the SBP as a time-dependent variable, we found, for the active treatment group only, that a decrease of 5 mm Hg in DBP increased the risk for stroke (relative risk, [RR], 1.14; 95% confidence interval [CI], 1.05-1.22), for CHD (RR, 1.08; 95% CI, 1.00-1.16), and for CVD (RR, 1.11; 95% CI, 1.05-1.16). CONCLUSIONS: Some patients with ISH may be treated to a level that uncovers subclinical disease, and some may be overtreated. Further studies need to determine whether excessively low DBP can be prevented by more careful titration of antihypertensive therapy while maintaining SBP control. It is reassuring that patients receiving treatment for ISH never perform worse than patients receiving placebo in terms of CVD events.

Diuretics and beta-blockers do not have adverse effects at 1 year on plasma lipid and lipoprotein profiles in men with hypertension. Department of Veterans Affairs Cooperative Study Group on Antihypertensive Agents.

BACKGROUND: Concern based on the reported short-term adverse effects of antihypertensive agents on plasma lipid and lipoprotein profiles (PLPPs) has complicated the therapy for hypertension. OBJECTIVE: To compare the long-term (1-year) effects of 6 different antihypertensive drugs and placebo on PLPPs in a multicenter, randomized, double-blind, parallel-group clinical trial in 15 US Veterans Affairs medical centers. PATIENTS AND METHODS: A total of 1292 ambulatory men, 21 years or older, with diastolic blood pressures (DBPs) ranging from 95 to 109 mm Hg taking placebo were randomized to receive placebo or 1 of 6 antihypertensive drugs: hydrochlorothiazide, atenolol, captopril, clonidine, diltiazem, or prazosin. After drug titration, patients with a DBP of less than 90 mm Hg were followed up for 1 year. Plasma lipids and lipoprotein profiles were determined at baseline, after initial titration, and at 1 year. RESULTS: After 8 weeks on a regimen of hydrochlorothiazide, increases of 3.3 mg/dL (0.09 mmol/L) in total cholesterol and 2.7 mg/dL in apolipoprotein B were significantly different (P< or =.05) from decreases of 9.3 mg/dL in total cholesterol and 5.4 mg/dL in ApoB levels while receiving prazosin but not from placebo. Patients achieving positive DBP control using hydrochlorothiazide (responders) showed no adverse changes in PLPPs, whereas nonresponders exhibited increases in triglycerides, total cholesterol, and low-density lipoprotein cholesterol levels. Plasma lipids and lipoprotein profiles did not change significantly among treatment groups after 1 year except for minor decreases in high-density lipoprotein 2 levels using hydrochlorothiazide, clonidine, and atenolol. CONCLUSIONS: None of these 6 antihypertensive drugs has any long-term adverse effects on PLPPs and, therefore, may be safely prescribed. Previously reported short-term adverse effects from using hydrochlorothiazide are limited to nonresponders.

Nonpharmacologic intervention to reduce blood pressure in older patients with mild hypertension.

BACKGROUND: Although nonpharmacologic interventions are widely recommended in the therapy of high blood pressure in older adults, surprisingly little data exist to confirm the efficacy of these interventions in older persons. METHODS: We conducted a randomized, controlled clinical trial in persons aged 60 to 85 years with a diastolic blood pressure of 85 to 100 mm Hg. The experimental arm was a nonpharmacologic intervention combining weight reduction, sodium restriction, and increased physical activity. The nonpharmacologic intervention consisted of eight weekly group and two individual sessions during the intensive phase, followed by four monthly group sessions during the maintenance phase. The control group received no treatment during the study. Blood pressure was assessed by certified technicians (blinded to group assignment) using random zero sphygmomanometers. RESULTS: Of 56 participants randomized, 47 completed the entire 6-month trial (21 in the intervention group and 26 in the control group). Attendance at the intervention sessions was excellent. The intervention group lost more weight (-2.1 kg) over 6 months than the control group (+0.3 kg). Trends for decreasing 24-hour urine sodium excretion in both the intervention and control groups, with greater trend in the intervention group, were not statistically significant. The intervention group experienced more reduction in systolic and diastolic blood pressure than did the control group (mean differences between groups at 6 months, 4.2/4.9 mm Hg, respectively). CONCLUSIONS: Our data indicate that a nonpharmacologic intervention will lower systolic and diastolic blood pressure levels in older people with borderline or mild elevations of diastolic blood pressure.

Diuretic-based treatment and cardiovascular events in patients with mild renal dysfunction enrolled in the systolic hypertension in the elderly program.

BACKGROUND: It is expected that the treatment of hypertension in patients with renal disease decreases the risk of cardiovascular events, but the evidence in these patients is lacking. OBJECTIVE: To assess the effect of diuretic-based treatment on cardiovascular events in patients with isolated systolic hypertension and renal dysfunction. METHODS: A total of 4336 persons aged 60 years and older with systolic blood pressures of 160 mm Hg and higher and diastolic blood pressures of less than 90 mm Hg were randomly assigned to receive either placebo or chlorthalidone (12.5-25.0 mg/d), with the addition of atenolol (25-50 mg/d) or reserpine (0.05-0.10 mg/d) if needed, and observed for 5 years. The risk of first-occurring cardiovascular events, including stroke, transient ischemic attack, myocardial infarction, heart failure, coronary artery bypass surgery, angioplasty, aneurysm, endarterectomy, sudden death, or rapid death, was stratified according to baseline serum creatinine levels (35.4-84.0, 84.1-101.6, 101.7-119.3, and 119.4-212.2 micromol/L [0.4-0.9, 1.0-1.1, 1.2-1.3, and 1.4-2.4 mg/dL]). RESULTS: Systolic blood pressure reduction was not affected by baseline serum creatinine levels. Active treatment did not affect the risk of serum creatinine levels becoming elevated during follow-up. The risk of hypokalemia with active treatment decreased significantly with increasing baseline serum creatinine levels. In the 4 baseline serum creatinine groups, the relative risk (95% confidence interval) of cardiovascular events developing with active treatment was 0.73 (0.54-0.97), 0.63 (0.49-0.82), 0.62 (0.44-0.87), and 0.59 (0.38-0.91). The results were similar for the outcomes of stroke or coronary artery events and in analyses stratified by sex or age. CONCLUSION: Diuretic-based treatment of patients with isolated systolic hypertension prevents the development of cardiovascular events in older persons with mild renal dysfunction.

Treatment of hypertension in the elderly. III. Response of isolated systolic hypertension to various doses of hydrochlorothiazide: results of a Department of Veterans Affairs cooperative study. Department of Veterans Affairs Cooperative Study Group on Antihypertensive Agents.

In a double-blind randomized study, we evaluated the effects of 25 mg vs 50 mg of hydrochlorothiazide in 51 elderly patients (aged 68.9 +/- 7.0 years) with isolated systolic hypertension (blood pressure, 160 to 239 mm Hg systolic and less than 90 mm Hg diastolic). Dose levels could be increased to twice daily to control blood pressure. The reductions in blood pressure (25.4/6.8 mm Hg and 28.9/7.4 mm Hg) and proportion of patients in whom blood pressure was controlled (78% and 89%) were similar in the lower- and higher-dose groups during the titration phase. However, serum potassium level was reduced more in the higher-dosage (0.57 mmol/L) than the lower-dosage (0.17 mmol/L) group. There were no significant changes in blood pressure during a 24-week maintenance phase. No patient required withdrawal from the study because of adverse effects, and cognitive-behavioral function was well preserved. We conclude that hydrochlorothiazide is effective and well tolerated in older patients with isolated systolic hypertension, many of whom may be effectively treated with 25 mg of hydrochlorothiazide once daily.

Response to a second single antihypertensive agent used as monotherapy for hypertension after failure of the initial drug. Department of Veterans Affairs Cooperative Study Group on Antihypertensive Agents.

BACKGROUND: An important issue in clinical practice is how to treat patients whose blood pressure does not respond to the first antihypertensive drug selected. OBJECTIVE: To analyze the antihypertensive response of patients who had failed to achieve their diastolic blood pressure goal (< 90 mm Hg at the end of 8 to 12 weeks of titration) with one of six randomly allocated drugs or placebo to the random allocation of an alternate drug. METHODS: We initially randomized 1292 men with diastolic blood pressure of 95 to 109 mm Hg to treatment with hydrochlorothiazide, atenolol, captopril, clonidine hydrochloride, diltiazem hydrochloride (sustained release), prazosin hydrochloride, or placebo. Of 410 men in whom initial treatment failed, 352 qualified for randomization to the alternate drug. RESULTS: Of the 352 patients, 173 (49.1%) achieved their goal diastolic blood pressure, in 133 (37.8%) the alternate drug failed, and 46 (13.1%) left the study for various reasons. Overall response rates were as follows: diltiazem, 63%; clonidine, 59%; prazosin, 47%; hydrochlorothiazide, 46%; atenolol, 41%; and captopril, 37%. The best response rate for patients in whom hydrochlorothiazide failed was achieved with diltiazem (70%); after atenolol failure, clonidine (86%); after captopril failure, prazosin (54%); after clonidine failure, diltiazem (100%); after diltiazem failure, captopril (67%); and after prazosin failure, clonidine (53%). The combined response rate for patients initially randomized to an active treatment was 76.0%, which is similar to that achieved by the combination of two drugs in previous studies. CONCLUSIONS: We conclude that sequential single-drug therapy is a rational approach for treatment of hypertension in patients in whom initial drug therapy has failed.

Prevention and Treatment of Hypertension Study (PATHS): effects of an alcohol treatment program on blood pressure.

OBJECTIVE: To determine whether blood pressure is reduced for at least 6 months with an intervention to lower alcohol intake in moderate to heavy drinkers with above optimal to slightly elevated diastolic blood pressure, and whether reduction of alcohol intake can be maintained for 2 years. DESIGN: A randomized controlled trial. METHODS: Six hundred forty-one outpatient veterans with an average intake of 3 or more alcoholic drinks per day in the 6 months before entry into the study and with diastolic blood pressure 80 to 99 mm Hg were randomly assigned to a cognitive-behavioral alcohol reduction intervention program or a control observation group for 15 to 24 months. The goal of the intervention was the lower of 2 or fewer drinks daily or a 50% reduction in intake. A subgroup with hypertension was defined as having a diastolic blood pressure of 90 to 99 mm Hg, or 80 to 99 mm Hg if recently taking medication for hypertension. RESULTS: Reduction in average weekly self-reported alcohol intake was significantly greater (P<.001) at every assessment from 3 to 24 months in the intervention group vs the control group: levels declined from 432 g/wk at baseline by 202 g/wk in the intervention group and from 445 g/wk by 78 g/wk in the control group in the first 6 months, with similar reductions after 24 months. The intervention group had a 1.2/0.7-mm Hg greater reduction in blood pressure than the control group (for each, P = .17 and P = .18) for the 6-month primary end point; for the hypertensive stratum the difference was 0.9/0.7 mm Hg (for each, P = .58 and P = .44). CONCLUSIONS: The 1.3 drinks per day average difference between changes in self-reported alcohol intake observed in this trial produced only small nonsignificant effects on blood pressure. The results from the Prevention and Treatment of Hypertension Study (PATHS) do not provide strong support for reducing alcohol consumption in nondependent moderate drinkers as a sole method for the prevention or treatment of hypertension.

Vasopressin elevation in essential hypertension and increased responsiveness to sodium intake.

The relationship of arterial pressure (AP) to plasma arginine vasopressin (AVP) and sodium (Na) intake was determined in untreated essential hypertensive (H) and normotensive (N) subjects. The AP of H subjects averaged 147/101 mm Hg and that of N subjects, 124/79 mm Hg. Plasma AVP was elevated significantly in H subjects, averaging 8.5 pg/ml compared to 4.7 pg/ml in N subjects. Multivariant regression analysis yielded a significant correlation (r2 = 0.34) between diastolic pressure, urine Na concentration, and changes in plasma AVP. Plasma Na of H subjects averaged 2.0 mEq/liter less and urine Na concentration 22 mEq/liter less than in N subjects. Sodium intake appeared to have no influence on the plasma AVP of N subjects, but H subjects excreting Na in excess of 250 mEq/day averaged a plasma AVP twice as high as that in H subjects excreting less than 150 mEq/day. In H subjects, the influence of Na intake appeared to be related to age. In subjects less than 50 years of age, Na intake did not appear to influence chronic levels of plasma AVP, while in subjects older than 50 years who were excreting Na in excess of 250 mEq/day, plasma AVP levels were twice (13.5 pg/ml) those observed in hypertensives of the same age excreting less than 150 mEq/ day (6.5 pg/ml). The data indicate that plasma AVP tends to be elevated in moderate essential hypertension. Reduced concentrating ability of the kidneys of these subjects is suggested by decreased urine Na concentrations despite elevated plasma AVP. The observed increases of plasma AVP could be exerting a direct influence on extra- and intravascular volumes by renal and systemic vasoconstriction.

Treatment of hypertension in the elderly: I. Blood pressure and clinical changes. Results of a Department of Veterans Affairs Cooperative Study.

We compared the efficacy and adverse effects of antihypertensive drug regimens in 690 men past age 60 with diastolic blood pressure 90-114 mm Hg and systolic blood pressure less than 240 mm Hg. They received either a low (25-50 mg) or high (50-100 mg) dose of hydrochlorothiazide daily. Of 644 patients who completed the hydrochlorothiazide titration, 375 (58.2%) were responders (diastolic blood pressure less than 90 and less than or equal to 5 mm Hg below baseline) and 92.8% of these completed a 6-month maintenance period. Blood pressure was reduced from 157.6/98.5 mm Hg by 18.3/9.5 mm Hg with low dose hydrochlorothiazide and by 20.4/9.6 mm Hg with high dose hydrochlorothiazide; more patients achieved goal blood pressure with the high dose. Whites and blacks responded equally. Serum potassium less than 3.5 mmol/l occurred in 104 of 321 (32.3%) of the high dose versus 62 of 333 (18.6%) of the low dose hydrochlorothiazide patients. The 269 nonresponders to hydrochlorothiazide were randomly assigned in a double-blind study to receive hydralazine, methyldopa, metoprolol, or reserpine in addition to hydrochlorothiazide; 79.2% responded to the addition of the second drug and 87.3% of these completed a 6-month maintenance phase. Overall, there were no significant efficacy differences among the step 2 regimens. We conclude that the lower dose of hydrochlorothiazide was nearly as effective as the higher dose, and the addition of a second drug was effective and generally well tolerated in elderly patients.

Treatment of hypertension in the elderly: II. Cognitive and behavioral function. Results of a Department of Veterans Affairs Cooperative Study.

This study was designed to determine whether blood pressure reduction, per se, causes adverse effects on cognitive and behavioral function in elderly hypertensive patients. Men with mild-to-moderate diastolic hypertension who had passed their 60th birthday were entered into the trial. After a placebo washout period, they were assigned in a randomized, double-blind manner to one of two groups receiving hydrochlorothiazide (either 25 mg once or twice daily or 50 mg once or twice daily). Responders entered a 1-year maintenance period. Nonresponders were randomly assigned to double-blind treatment with hydralazine, methyldopa, metoprolol, or reserpine added to the diuretic therapy. During the placebo and treatment periods, patients underwent a battery of psychometric tests designed to assess cognitive function, motor skills, memory, and affect. A separate questionnaire assessed the patient's ability to perform activities of daily living. A subset of patients blindly being treated with placebo received the same battery of tests as a control for practice effect. The results showed that there was similar improvement on the psychometric tests between those patients whose blood pressure was successfully reduced and the placebo-treated control group. Therefore, the practice effect did not obscure a true deterioration in function. There were no substantive differences between the lower and higher doses of diuretic or among the four drugs added to the diuretic, although there were qualitative differences in side effects. We conclude that blood pressure reduction, per se, does not adversely affect cognitive and behavioral function in elderly hypertensive patients and that antihypertensive treatment is safe and effective in these patients.

Evidence for the efficacy of low-dose diuretic monotherapy.

Diuretic monotherapy has been recommended by the fifth report of the Joint National Committee on Detection, Evaluation and Treatment of High Blood Pressure (JNC-V) as a preferred initial treatment for hypertension. Thiazide diuretics are commonly used to treat hypertension because of their demonstrated efficacy, favorable safety profile, low acquisition cost, and their proven ability to reduce blood pressure-related morbidity and mortality. Once-daily low-dose hydrochlorothiazide (12.5 mg/ day) or chlorthalidone (15 mg/day) effectively reduces blood pressure in patients with stage 1 or stage 2 hypertension in comparison with placebo. Blood pressure reductions with low-dose hydrochlorothiazide and chlorthalidone are comparable to that achieved with higher doses (25 and 50 mg/day). Additional blood pressure reductions can be attained with concomitant use of once-daily low-dose hydrochlorothiazide or chlorthalidone with an angiotensin-converting enzyme (ACE) inhibitor, a beta blocker, or a calcium antagonist. Once-daily low-dose hydrochlorothiazide provides clinically meaningful blood pressure lowering while minimizing adverse effects, such as electrolyte disturbances, cholesterol elevations, and increases in serum uric acid levels.

Comparison of plasma lipid and lipoprotein profiles in hypertensive black versus white men. Department of Veterans Affairs Cooperative Study Group on Antihypertensive Agents.

An abnormal plasma lipid and lipoprotein profile is an independent and strong predictor of mortality and morbidity from coronary artery disease (CAD). We report on plasma lipid and lipoprotein profiles with respect to race, age, obesity, blood pressure (BP), smoking, and drinking history in 1,292 male veterans with a diastolic BP of 95 to 109 mm Hg while off antihypertensive medications. Blacks had 24% (p <0.001) lower triglycerides than whites. In contrast, the following parameters were higher in blacks than in whites by the indicated percentages: high-density lipoprotein (HDL) cholesterol, 16% (p <0.001); HDL2 cholesterol, 36% (p <0.001); apolipoprotein (Apo) A1, 8% (p <0.001); HDL/low-density lipoprotein (LDL), 18% (p = 0.018); HDL2/LDL, 36% (p = 0.031); HDL2/HDL3, 21% (p <0.001); and Apo A1/Apo B, 15% (p <0.001). Triglycerides were unchanged up to age 60, but were lower by 24% (p <0.001) in those aged > or = 70. Apo A1 levels were higher (p <0.001), whereas LDL cholesterol was lower (p <0.008) in moderate alcohol consumers versus abstainers. Triglycerides were higher (p <0.001), whereas HDL, HDL2 cholesterol, and Apo A1 were lower (p <0.001) with increasing obesity. Moderate alcohol consumption had a strong favorable effect on HDL, HDL2, and HDL3 cholesterol among subjects of normal weight, but this effect was diminished in obese subjects. Total and LDL cholesterol were higher by 6.4% (p = 0.001) and 9.4% (p <0.003), respectively, whereas HDL cholesterol remained unchanged in those with diastolic BP of 105 to 109 mm Hg versus those with diastolic BP of 95 to 99 mm Hg. We conclude that hypertensive black men have lipid and lipoprotein profiles indicative of less CAD risk than white men. Chronic moderate alcohol consumption correlates with a favorable plasma lipid and lipoprotein profile in normal, but not obese, men. Obesity is associated with an adverse plasma lipid and lipoprotein profile. Thus, race, alcohol intake, and obesity may be important modifiers of CAD in untreated hypertensive men.

The clinical significance of systolic hypertension.

Large-scale epidemiologic studies and clinical trials have contributed to an increased recognition of the importance of systolic hypertension. Data from landmark epidemiologic studies such as the Multiple Risk Factor Intervention Trial screenee follow-up and the Framingham Heart Study have demonstrated that elevated systolic blood pressure dramatically increases the risk of cardiovascular events. Of particular concern is the extremely high risk associated with isolated systolic hypertension (ISH), which is much more common in the elderly than in young adults. Clinical trials have identified significant risk reductions after treatment with diuretics or the dihydropyridine calcium antagonist nitrendipine in older individuals with ISH. Beta blockers have not been associated with such benefits. The recently released sixth report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC VI) recommends drug therapy for all patients with stage 1 (140 to 159 mm Hg) or stage 2-3 (> or = 160 mm Hg) systolic hypertension, whether it occurs in isolation or in conjunction with diastolic hypertension. The sixth JNC report identified diuretics as the initial therapy of choice, with a long-acting dihydropyridine calcium channel blocker as an alternative if diuretics are ineffective or not well tolerated. More research is needed to evaluate other classes of drugs in this setting. Regardless of the choice of therapy, patients should be encouraged to adopt lifestyle modifications such as weight loss, exercise, sodium restriction, and reduced alcohol consumption.

Clinical overview of hypertension and emerging treatment considerations.

Managing hypertension is a complex undertaking, where even the definition of the disorder is subject to discussion. Recently, there has been controversy concerning the most appropriate measure to determine health risks associated with hypertension. In the past, diastolic blood pressure (DBP) was the prime measure for defining hypertension, but currently systolic blood pressure (SBP) and pulse pressure have gained favor. Evidence now suggests that all three measures should be considered as part of the hypertensive profile, with the patient's age determining the relative importance of each. Aggressive treatment of hypertension may reduce morbidity and mortality. Data from trials clearly indicate that, for all stages of hypertension, the goal should be a maximum SBP of <150 mm Hg and a DBP of <90 mm Hg, with DBP values as low as 70 mm Hg being safe. For individuals with diabetes mellitus, these target values should be even lower--SBP <140 mm Hg and DBP <80 mm Hg. As a significant number of deaths attributable to hypertension occur in patients who are not diagnosed as hypertensive but whose blood pressure (BP) is above the optimal level of 120/80 mm Hg, lowering BP levels in this group is recommended as well, with lifestyle modification being first-line therapy. Because controlling BP to <140/90 mm Hg often requires the use of two or three agents, the tolerability of the entire regimen must be considered. However, with the multitude of antihypertensive drugs currently available, no patient's BP should remain above the 150/90 mm Hg level.

Chronic effect of KCl on black-white differences in plasma renin activity, aldosterone, and urinary electrolytes.

In a 10-week trial of the effect of 80 mEq KCl/day on blood pressure, the following biochemical changes were noted: plasma renin activity (PRA), originally significantly lower in blacks than whites, increased to the same level as whites after K supplementation. A similar trend was noted with aldosterone. KCl increased creatinine excretion in blacks and whites, and lowered Ca excretion in blacks. These results suggest that the low PRA found in blacks is due, at least in part, to low K intake, and not to genetic causes.

Department of veterans Affairs single-drug therapy of hypertension study. Revised figures and new data. Department of Veterans Affairs Cooperative Study Group on Antihypertensive Agents.

The antihypertensive efficacy of six drugs and placebo was compared in 1292 men with untreated diastolic blood pressure of 95 to 109 mm Hg. The primary end point "success" was defined as the patient having achieved a diastolic blood pressure of < 90 mm Hg at the end of the drug titration period and having maintained a diastolic blood pressure of < 95 mm Hg for 1 year without drug intolerance. The original published success rate data (N Engl J Med 1993;328:914-921) were discovered to be in error due to a computer programming code omission (N Engl J Med 1994;330:1689). This paper presents corrected graphic figures. The corrected success rates were generally higher than originally published. Overall, diltiazem (72%) was significantly higher than hydrochlorothiazide (55%), prazosin (54%), captopril (50%), and placebo (31%); clonidine (62%) and atenolol (60%) were intermediate. There were some changes in the hierarchy of drug response, but important differences in success rates according to age by race subgroups remained. Whites responded well to all drug classes, except for lower efficacy of hydrochlorothiazide in younger whites. Blacks responded better to diltiazem than other agents. In addition, we have analyzed the data using a definition of success based on < 90 mm Hg for 1 year. Use of the <90 mm Hg criterion reduced the rate of success, but had only a minor effect on the drug success rate hierarchy. We conclude that single-drug antihypertensive therapy is effective in a majority of stage 1 to 2 diastolic hypertensive patients, although there are important age-by-race differences in success rates among various drug classes.

Use of the factorial design and quadratic response surface models to evaluate the fosinopril and hydrochlorothiazide combination therapy in hypertension.

The combination of angiotensin converting enzyme (ACE) inhibitor and thiazide diuretic has advantages over monotherapy for the treatment of hypertension. Previous study designs have often been inadequate to demonstrate the details of interactions between these antihypertensive agents. This study used a modified 4 x 4 factorial randomized, double-blind, placebo-controlled, parallel group design to study the efficacy of 17 different doses of fosinopril (Fos), a phosphinic acid derived ACE inhibitor, and hydrochlorothiazide (HCTZ) in 550 patients with mild to moderate hypertension. Data from these variables were fit to quadratic response surface models (QRSM) using polynomial functions in the doses of the two components. Using QRSM, seated systolic (SeSBP) and diastolic blood pressure (SeDBP) responses at 8 weeks were predicted for actual doses and interpolated for intermediate doses not studied. Fos and HCTZ alone and in combination produced a dose-related reduction in SeSBP and SeDBP. Using 10 mg Fos + 12.5 mg HCTZ reduced the adjusted mean SeDBP 6.3 mm Hg and 20 mg Fos + 12.5 mg HCTZ lowered the same measure 9.1 mm Hg. Coadministration of Fos and HCTZ produced an additive antihypertensive effect. This study of combination agents for hypertension using a factorial design with QRSM accurately predicts dose responses and is a valuable clinical trial methodology.

Effect of back support and stethoscope head on seated blood pressure determinations.

Seated BP measurements were taken in 48 men with a history of essential hypertension: in a chair with back support v on an examining table with no back support, and with bell v diaphragm stethoscope head in each condition. There were no significant differences between bell and diaphragm in SBP or DBP determinations. SBP was not significantly different between table and chair, but table DBP was 6.5 mm Hg higher (P less than .0001) than chair DBP. We conclude that back support, but not bell v diaphragm stethoscope head, affects seated BP determinations.