Pulse pressure changes with six classes of antihypertensive agents in a randomized, controlled trial.

Pulse pressure has been more strongly associated with cardiovascular outcomes, especially myocardial infarction and heart failure, than has systolic, diastolic, or mean arterial pressure in a variety of populations. Little is known, however, of the comparative effects of various classes of antihypertensive agents on pulse pressure. In retrospective analyses of the Veterans Affairs Single-Drug Therapy for Hypertension Study, we compared changes in pulse pressure with 6 classes of antihypertensive agents: 1292 men with diastolic blood pressure of 95 to 109 mm Hg on placebo were randomized to receive hydrochlorothiazide, atenolol, captopril, clonidine, diltiazem, prazosin, or placebo. Drug doses were titrated to achieve a goal diastolic blood pressure of <90 mm Hg during a 4- to 8-week medication titration phase. Pulse pressure change (placebo subtracted) was assessed from baseline to the end of the 3-month titration and 1-year maintenance. Mean baseline systolic, diastolic, and pulse pressures were 152, 99, and 53 mm Hg, respectively. Reductions in pulse pressure during titration were greater (P<0.001) with clonidine (6.7 mm Hg) and hydrochlorothiazide (6.2 mm Hg) than with captopril (2.5 mm Hg), diltiazem (1.6 mm Hg), and atenolol (1.4 mm Hg); reduction with prazosin (3.9 mm Hg) was similar to all but clonidine. After 1 year, pulse pressure was reduced significantly more (P<0.001) with hydrochlorothiazide (8.6 mm Hg) than with captopril and atenolol (4.1 mm Hg with both); clonidine (6.3 mm Hg), diltiazem (5.5 mm Hg), and prazosin (5.0 mm Hg) were intermediate. These data show that classes of antihypertensive agents differ in their ability to reduce pulse pressure. Whether these differences affect rates of cardiovascular events remains to be determined.

Ventricular and myocardial function following treatment of hypertension.

This study assesses and evaluates left ventricular (LV) contractile function after treatment of hypertension, with an emphasis on LV midwall mechanics. Although prior studies have assessed cardiac function after hypertension treatment, none has performed an analysis of LV midwall mechanics. The Veterans Affairs Study of monotherapy in hypertension was a study large enough to permit analysis of midwall mechanics across a wide spectrum of mass changes accompanying hypertension treatment. LV chamber function was assessed by computing fractional shortening at the endocardial surface; LV midwall shortening was used to define myocardial function. Both shortening indexes were related to end-systolic circumferential stress in the entire population by partitioning values of mass and relative wall thickness changes. Two hundred sixty-eight patients were studied at baseline and again after a 1- or 2-year period. In the entire group, there was no significant change in circumferential shortening either at the endocardium (38 +/- 8% at baseline vs 37 +/- 7% at follow up, p = 0.29) or in shortening at the midwall (20 +/- 3% vs 20 +/- 3%, p = 0.53). However, 83 patients had a reduction in relative wall thickness and an increase in midwall shortening. The change in midwall shortening was significantly related to changes in relative wall thickness (r = -0.53, p = 0.0001). Thus, reductions in LV mass associated with antihypertensive therapy are generally not accompanied by a decrement in LV chamber or myocardial function. Improvement in midwall shortening is more closely related to normalization of LV geometry than to reduction in LV mass.

Placebo-associated blood pressure response and adverse effects in the treatment of hypertension: observations from a Department of Veterans Affairs Cooperative Study.

BACKGROUND: The use of placebo in clinical trials has been vigorously debated. Placebo control may be useful in disease states, such as stage 1 and stage 2 hypertension as defined by the Sixth Report of the Joint National Committee on Detection, Evaluation and Treatment of High Blood Pressure (JNC VI), in which response rates for placebo are high or close to response rates for effective therapies, or when established interventions have significant adverse effects. OBJECTIVE: To compare rates for the control of blood pressure and adverse effects of placebo vs active treatment in patients with stage 1 and stage 2 hypertension. METHODS: This study is a randomized controlled trial evaluating the blood pressure response and adverse effects of placebo vs 6 active treatments administered in 15 Veterans Affairs hypertension centers. The 1292 subjects of the Veterans Affairs Cooperative Study receiving single-drug therapy for hypertension were randomly allocated to receive treatment with 1 of 6 active drugs (n= 1105) or placebo (n=187). Treatment success was defined as maintaining a diastolic blood pressure of less than 95 mm Hg for at least 1 year. We compared treatment success rates for the control of blood pressure and adverse effects of placebo vs active treatment. Using the Kaplan-Meier method, we also compared rates of discontinuation from placebo vs active drug treatment over time as a result of adverse drug effects and blood pressure exceeding safety limits. RESULTS: At the end of the titration phase, 58 patients who were treated with placebo (31%) achieved a goal diastolic blood pressure lower than 90 mm Hg and 57 (30%) achieved success at 1 year. Older white patients who received placebo had a success rate of 38% vs 23% to 27% for the other age-race subgroups. The rates of discontinuation as a result of adverse drug effects were 13% for patients receiving placebo vs 12% for patients receiving active treatment (P=.40). The rates of discontinuation for blood pressure being too high were 14% for patients receiving placebo vs 7% for patients receiving active treatment (P=.01). CONCLUSIONS: Placebo control provides an important benchmark for both efficacy and adverse effects. It continues to have an appropriate place in certain therapeutic trials, particularly those involving the treatment of stage 1 and stage 2 hypertension.

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.

Accessing data from external centralized sources to enhance analysis of a completed clinical trial.

After the data collection phase of a clinical trial has been completed, new hypotheses may surface which require additional data before they can be tested. In the Veterans Affairs Cooperative Study on Single Drug Therapy of Hypertension, we investigated the relationship between location of the participating center, race and ability to control blood pressure. The analysis indicated poorer blood pressure control among sites located in the "stroke belt" (southeastern United States), especially among African-Americans. We sought to determine whether the effect was attributable to socioeconomic patterns; however, income data were not collected as part of the original study. Therefore, we accessed centralized data bases to obtain zipcode-level income information for the randomized study patients. This approach yielded estimates of income data for 94.3% of the patients and compared favorably to data acquisition rates for variables which were collected prospectively in the study.

Reducing the risk of malpractice claims.

Many physicians will be sued for malpractice at some time during their careers. Risk of litigation can be reduced by adopting practices that include keeping thorough medical records, educating office personnel, and fostering good patient-physician relationships. The last is important because patients who view their physicians as caring tend not to sue even if an adverse outcome occurs.

Clinical presentation and management of patients with uncontrolled, severe hypertension: results from a public teaching hospital.

CONTEXT: There is relatively little data available on the management of patients with severe, uncomplicated hypertension and severe hypertension with stable hypertensive complications. OBJECTIVE: To determine the incidence, clinical features, acute management, and clinical course of severe, uncomplicated hypertension and severe hypertension with stable hypertensive complications presenting for emergency department care in a large public teaching hospital. DESIGN: Chart survey of consecutive emergency department visits. PATIENTS: Ninety-one of 2898 consecutive visits to a public teaching hospital emergency department were specifically for severe, uncomplicated hypertension. RESULTS: Of 2898 consecutive medical emergency department visits, there were 142 (4.9%) patient visits specifically for systolic blood pressure (SBP) > or =220 mm Hg or diastolic blood pressure (DBP) > or =120 mm Hg. Ninety-one of the 142 patient visits were for severe hypertension in the absence of acute target organ impact or neuroretinopathy. Eighty-nine patients received acute drug therapy. Twenty-nine patients received two drugs, and 15 received three drugs. Sixty-eight patients (75%) received clonidine, and 15 (16.5%) received short-acting nifedipine despite widely published concerns about the safety of this practice. We found a wide variability of blood pressure response to treatment. The average decline in SBP was 50+/-31 mm Hg and the average decline of DBP was 34+/-20 mm Hg over 4.2+/-2.9 h. Forty-two patients (46%) had the SBP reduced to less than 160 mm Hg, and 46 patients (50%) the DBP to less than 100 mm Hg. Long-term management and follow-up were suboptimal. Of 74 patients discharged from the emergency room, 22 patients (30%) returned because of uncontrolled hypertension within an average of 33+/-28 days, 10 patients with hypertensive complications. CONCLUSIONS: Severe hypertension continues to present an important and common problem. Physicians appear to place a strong emphasis on acute lowering of the blood pressure to near-normal levels. Patients are frequently lost to follow-up and have a very high rate of recurrent emergency department visits and hypertensive complications. This study points to a need for detailed, specific practice guidelines and comprehensive disease management protocols for severe, uncomplicated hypertension.

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.

Effects of antihypertensive single-drug therapy on heart rate. Department of Veterans Affairs Cooperative Study Group on Antihypertensive Agents.

Heart rate increasingly is being recognized either as an independent risk factor for a wide variety of cardiovascular disorders or as a surrogate marker for them. We analyzed the changes in heart rate associated with antihypertensive therapy with six drugs and placebo from the VA Cooperative Study on Single-Drug Therapy. These results were published previously (American Journal of Hypertension 1998;11:597-601). This paper provides a summary of the earlier publication with the addition of three figures not previously published. Atenolol had the greatest effect on heart rate reduction, followed by clonidine and diltiazem-SR. Hydrochlorothiazide and captopril were associated with small reductions in heart rate over time, whereas prazosin increased heart rate. Patients whose blood pressure was controlled by placebo had a 3.1 beats/min reduction of heart rate at 2 years. When the baseline heart rate was 65 beats/min or less, all drugs increased the heart rate except for atenolol, which further reduced it. Although it is clear that each of the six drugs used in our study had a different effect on heart rate, we cannot state that drug-induced reduction in heart rate per se confers a decrease in cardiovascular risk.

Age-race subgroup compared with renin profile as predictors of blood pressure response to antihypertensive therapy. Department of Veterans Affairs Cooperative Study Group on Antihypertensive Agents.

CONTEXT: Renin profiling and age-race subgroup may help select single-drug therapy for stage 1 and stage 2 hypertension. OBJECTIVE: To compare the plasma renin profiling and age-race subgroup methods as predictors of response to single-drug therapy in men with stage 1 and 2 hypertension as defined by the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure. DESIGN: The Veterans Affairs Cooperative Study on Single-Drug Therapy of Hypertension, a randomized controlled trial. SETTING: Fifteen Veterans Affairs hypertension centers. PATIENTS: A total of 1105 ambulatory men with entry diastolic blood pressure (DBP) of 95 to 109 mm Hg, of whom 1031 had valid plasma and urine samples for renin profiling. INTERVENTIONS: Randomization to 1 of 6 antihypertensive drugs: hydrochlorothiazide, atenolol, captopril, clonidine, diltiazem (sustained release), or prazosin. MAIN OUTCOME MEASURE: Treatment response as assessed by percentage achieving goal DBP (<90 mm Hg) in response to a single drug that corresponded to patients' renin profile vs a single drug that corresponded to patients' age-race subgroup. RESULTS: Clonidine and diltiazem had consistent response rates regardless of renin profile (76%, 67%, and 80% for low, medium, and high renin, respectively, for clonidine and 83%, 82%, and 83%, respectively, for diltiazem for patients with baseline DBP of 95-99 mm Hg). Hydrochlorothiazide and prazosin were best in low- and medium-renin profiles; captopril was best in medium- and high-renin profiles (low-, medium-, and high-renin response rates were 82%, 78%, and 14%, respectively, for hydrochlorothiazide; 88%, 67%, and 40%, respectively, for prazosin; and 51%, 83%, and 100%, respectively, for captopril for patients with baseline DBP of 95-99 mm Hg). Response rates for patients with baseline DBP of 95 to 99 mm Hg by age-race subgroup ranged from 70% for clonidine to 90% for prazosin for younger black men, from 50% for captopril to 97% for diltiazem for older black men, from 70% for hydrochlorothiazide to 92% for atenolol for younger white men, and from 84% for hydrochlorothiazide to 95% for diltiazem for older white men. Patients with a correct treatment for their renin profile but incorrect for age-race subgroup had a response rate of 58.7%; patients with an incorrect treatment for their renin profile but correct for age-race subgroup had a response rate of 63.1% (P = .30). After controlling for DBP and interactions with treatment group, age-race subgroup (P<.001) significantly predicted response to single-drug therapy, whereas renin profile was of borderline significance (P= .05). CONCLUSIONS: In these men with stage 1 and stage 2 hypertension, therapeutic responses were consistent with baseline renin profile, but age-race subgroup was a better predictor of response.

Will angiotensin converting enzyme genotype, receptor mutation identification, and other miracles of molecular biology permit reduction of NNT?

Severe forms of hypertension demand treatment because they have a high incidence of morbidity and mortality that can be reduced by antihypertensive therapy. Stage 1-2 hypertension has a low morbidity and mortality; short-term benefits of treatment are harder to document. Managed care organizations know that members have a high turnover rate, so they are less interested in costly mass treatment to prevent a few future events. Stage 1-2 hypertension causes the vast majority of morbid events simply because a low incidence in a large population exceeds the lower absolute number of events in a small population with a high incidence. We must focus our efforts and resources on hypertensives at highest risk and thereby reduce the number needed to treat for 5 years (NNT) to avoid a morbid event. Obvious risks include hypertension severity, existing target organ damage, and concomitant diseases. Clues to the genetic etiology of primary hypertension are less obvious. DD genotype for angiotensin-converting enzyme (ACE) is associated with more left ventricular hypertrophy and greater risk for cardiovascular morbid events. Some genotypes of nitric oxide synthetase are associated with less effective production of NO and achieve less arterial vasodilation in response to stimuli. Many receptors have mutations that make them more or less functionally appropriate. Understanding these genetic factors may permit us in the future to focus appropriate drug therapy on the population most likely to benefit, thereby reducing NNT.

Effect of single-drug therapy on reduction of left atrial size in mild to moderate hypertension: comparison of six antihypertensive agents.

BACKGROUND: Cardiac effects of hypertension include increased left ventricular (LV) mass and LV hypertrophy, as well as increased left atrial size, a predictor of stroke and atrial fibrillation. Although literature on reduction of LV mass with antihypertensive therapy is extensive, little information is available on effects of treatment on left atrial size. METHODS AND RESULTS: Patients with mild to moderate hypertension (diastolic blood pressure 95 to 109 mm Hg) were randomly allocated to treatment with atenolol, captopril, clonidine, diltiazem, hydrochlorothiazide, or prazosin in a double-masked trial. Two-dimensional targeted M-mode echocardiography was used to assess left atrial size and LV mass at baseline, 8 weeks, and 1 and 2 years. Longitudinal analysis examined changes in left atrial size from the baseline study, statistically adjusting for age, race, pretreatment left atrial size and LV mass, and serial measurements of systolic blood pressure, body weight, urinary sodium excretion, and physical activity score. Without adjustment for covariates, only hydrochlorothiazide was associated with decreases in left atrial size from baseline at 8 weeks (-1.0 +/- 5.2 mm; P=0.052), 1 year (-2.0 +/- 5.1 mm; P=0.02), and 2 years (4.6+/-7.2 mm; P=0.002). After adjustment for effects of covariates, patients with normal left atrial size had greater reduction (-3.3 mm) in left atrial size at 2 years with hydrochlorothiazide than with any other drug. For patients with left atrial enlargement, left atrial size decreased significantly with hydrochlorothiazide, atenolol, clonidine, and diltiazem at 1 year and with all treatments at 2 years. However, reduction at 2 years was greater with hydrochlorothiazide than with captopril or prazosin. CONCLUSIONS: Antihypertensive drugs differ in their effects on left atrial size. Hydrochlorothiazide was associated with greater overall reduction of left atrial size than other drugs effective for the treatment of hypertension. Reduction of left atrial size with therapy is in part independent of factors known to influence left atrial size, including LV mass and reduction of LV mass with treatment. The clinical benefit of reducing left atrial size with antihypertensive treatment remains to be determined.

Comparison of effects of antihypertensive drugs on heart rate: changes from baseline by baseline group and over time. Department of Veterans Affairs Cooperative Study Group on Antihypertensive Agents.

Baseline heart rate is becoming recognized as a predictor of cardiovascular risk. Various antihypertensive drugs have differing effects on heart rate. A randomized controlled clinical trial of 1292 ambulatory men with stage 1 or 2 hypertension was conducted in 15 Veterans Affairs medical centers. Patients were treated with hydrochlorothiazide, atenolol, captopril, clonidine, diltiazem, prazosin, or placebo for up to 2 years. Heart rates were measured at baseline, the end of titration, 1 year, and 2 years. Data were also stratified by baseline heart rate. A subset of patients had heart rate also determined by electrocardiogram. All drugs except prazosin reduced heart rate from baseline; additional small decreases were obtained over time with hydrochlorothiazide and placebo. The decrease initially achieved with clonidine was attenuated over time. The overall reduction in heart rate was greatest for atenolol (-12.2 beats/min) and least for prazosin (+3.8 beats/min). Only atenolol effected a further reduction of heart rate for patients whose baseline rate was < or =65 beats/min. All drugs reduced heart rate when the baseline was > or =85 beats/min. Data derived by electrocardiogram yielded similar results. The drugs used in this study differ in their ability to reduce heart rate, sustain that reduction over time, and to change heart rate in groups with high or low rates at baseline. The importance of these comparative changes as independent cardiac risk factor variables remains to be determined.

Safety of long-acting dihydropyridine calcium channel blockers in hypertensive patients.

Issues raised recently concerning the safety of calcium channel blockers (CCBs) prompted an analysis of the occurrence of cardiovascular events and death in the Pfizer Inc. hypertension clinical trial databases for amlodipine (Norvasc) and nifedipine in the gastrointestinal therapeutic system (GITS) formulation (Procardia XL). Prospectively defined analyses of data from comparative and noncomparative trials of amlodipine and nifedipine GITS were conducted. Outcome measures included cardiovascular and noncardiovascular deaths, and adverse cardiovascular events including new/worsened angina, myocardial infarction (MI), serious arrhythmia, stroke, congestive heart failure, and bleeding. Among all amlodipine-treated patients (n = 32,920), the incidence rates for all-cause death, MI, and new/worsened angina were 3.0, 3.3, and 1.6/1,000 patient-years of exposure, respectively. Among those in comparative trials alone (n = 4,126), the all-cause death rate was 4.1/1,000 patient-years, which was comparable to that of other non-CCB agents and significantly less than that of other CCBs (23.8/1,000 patient-years, p = 0.015), although the difference in rates represents only 2 deaths. Among all nifedipine-GITS-treated patients (n = 2,645), the rate of all-cause death was 4.1/1,000 patient-years, of MI 6.5/1,000 patient-years, and of new/ worsened angina 5.7/1,000 patient-years. The incidence rates for MI and other cardiac events were low in these hypertension trials, and did not differ among treatment groups in either the amlodipine or nifedipine GITS comparative analyses. In the clinical trial databases analyzed, there is no signal suggesting excessive risk of death or cardiovascular events for hypertensive patients treated with amlodipine or nifedipine GITS.