Lessons from combination therapy in Veterans Affairs Studies. Department of Veterans Affairs Cooperative Study Group on antihypertensive agents

Shake Rattle & Roll - Design and rationale for a pragmatic trial to improve blood pressure control among blacks with persistent hypertension

BACKGROUND

In Kaiser Permanente Northern California (KPNC), members had similar access to care and a very high overall rate of hypertension control. However, blacks had poorer blood pressure (BP) control than whites. The Shake Rattle & Roll (SRR) trial aimed to improve BP control rates in blacks and to reduce disparities in hypertension control.

METHODS

SRR was a cluster randomized controlled trial conducted at an urban medical center. All 98 adult primary care physicians (PCP) and their panels of hypertensive black patients were randomized, stratified by panel size, to one of three arms: 1) Usual Care (n = 33 PCPs, N = 1129 patients); 2) Enhanced Monitoring arm with an emphasis on improving pharmacotherapy protocol adherence (n = 34 PCPs, N = 349 patients); or 3) Lifestyle arm with a culturally tailored diet and lifestyle coaching intervention focusing on the Dietary Approaches to Stop Hypertension eating plan (n = 31 PCPs, N = 286 patients). The intervention period was for 12-months post-enrollment. Follow-up was planned for one and three years post-intervention completion. Primary outcome measure was the proportion of participants with controlled BP, defined as <140/90 mmHg, at 12-months post-enrollment. Secondary outcome included adverse cardiovascular events. An intention-to-treat analysis was carried out as the primary analysis.

CONCLUSION

SRR was a uniquely designed trial that included components from both pragmatic and explanatory methods. The pragmatic aspects allow for a more cost-effective way to conduct a clinical trial and easier implementation of successful interventions into clinical practice. However, there were also challenges of having mixed methodology with regards to trial conduction and analysis.

Racial differences in blood pressure response to calcium channel blocker monotherapy: a meta-analysis

BACKGROUND

A systematic literature review was conducted to determine whether US blacks and whites have differential blood pressure (BP) response to calcium channel blocker (CCB) monotherapy.

METHODS

Six published studies made up the final cohort of eligible articles. Multiple treatment groups within some studies led to a total of eight sets of estimates for BP reduction with a total of 6,851 white or nonblack participants and 3,371 black participants.

RESULTS

The pooled difference in systolic blood pressure (SBP) change between blacks and whites was -2.7 mm Hg (95% confidence interval (CI): -4.0, -1.3) with blacks having greater response. The difference in diastolic blood pressure (DBP) between blacks and whites was -0.4 mm Hg (95% CI: -1.0, 0.3) with blacks having greater response. Using a dichotomous outcome measure, whites were found to be just as likely as blacks to attain the DBP goal of <90 mm Hg or a 10 mm Hg or greater change (relative risk: 1.00 95% CI: 0.91, 1.11). In addition, examination of the continuous distribution of BP responses of whites and blacks showed over 90% overlap in treatment response.

CONCLUSION

Assessment of differential response to CCB monotherapy by race in published data depends on choice of outcome metric. Nonetheless, the results of this systematic review indicate that BP response is qualitatively similar in US blacks and whites, suggesting that patient race is not likely to offer any clinical utility for decisions about the likely effect of this antihypertensive therapy.

Polytherapy with two or more antihypertensive drugs to lower blood pressure in elderly Ontarians. Room for improvement

BACKGROUND

Although guidelines now recommend polytherapy to achieve blood pressure targets, little is know about which antihypertensive drugs are combined in clinical practice.

OBJECTIVE

To examine current practices for the coprescribing of antihypertensive agents.

METHODS

A population-based cohort study was performed using linked administrative databases on all Ontario residents 66 years of age or older who were newly treated for hypertension between July 1, 1994, and March 31, 2002, and did not have diabetes or other relevant comorbidities. All patients were followed for two years to determine which antihypertensives were prescribed concurrently.

RESULTS

Of the 166,018 patients in the described cohort, 1819 (1%) were prescribed a combination therapy tablet as their first-line therapy. The number of patients prescribed antihypertensive polytherapy within the first two years of diagnosis increased from 2071 (21%) of the 9825 hypertensive patients starting treatment in the second half of 1994 to 2578 (37%) of the 6988 hypertensive patients beginning treatment in the first quarter of 2002 (P<0.0001). Overall, 11,003 (27%) of polytherapy prescriptions were for drugs without additive hypotensive effects when combined and this proportion did not change over time.

CONCLUSIONS

Although there has been an increase in the use of polytherapy in elderly hypertensive patients without comorbidities in Ontario over the past decade, more than one-quarter of the two drugs prescribed together have not been proven to have additive hypotensive effects. Because this likely contributes to suboptimal blood pressure control rates, future guidelines and educational programs should devote increased attention to the choice of optimal polytherapy combinations.

Hypertension‐Related Morbidity and Mortality in African Americans—Why We Need to Do Better

Almost one third of adults in the United States have hypertension. Prevalence data among different racial or ethnic groups indicate that a disproportionate number of African Americans have hypertension compared with non-Hispanic whites and Mexican Americans. Earlier onset of high blood pressure and greater severity of hypertension contribute to a greater burden of hypertensive target organ damage in African Americans and may be a factor in the shorter life expectancy of this population compared with white Americans. There is a clear need for improved management of hypertension in African Americans via therapeutic lifestyle interventions and pharmacotherapy. While there is some evidence that particular antihypertensive agent classes provide blood pressure-lowering advantages over others, there is no support for withholding agents of any one class. When given as monotherapy, diuretics and calcium channel blockers may be relatively more effective in lowering blood pressure in African Americans than beta blockers, angiotensin-converting enzyme inhibitors, and angiotensin II receptor blockers. However, when combined with a diuretic, African Americans respond as well to these agents as other racial groups. Combination therapy using antihypertensive agents with differing modes of action provides additive antihypertensive efficacy and is well tolerated. Recent guidelines recommend combination therapy as the standard of care for patients with significant blood pressure elevation, especially those with diabetes mellitus and renal disease. These comorbidities are more common in African Americans and indicate the potential need for initial therapy with more than one agent or a combination of agents in one pill.

Rationale for Combination Therapy in the Management of Hypertension

Combination drug therapy in the management of hypertension has been used for many years. Recent recommendations of the Seventh Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure and the results of several new multiple-drug trials have focused on using the approach as initial therapy in many hypertensive patients. Results of these long-term outcome trials, as well as short-term and smaller studies, indicate the advantage of multiple-drug therapy in the management of hypertension.

Efficacy and tolerability of the perindopril/indapamide combination therapy for hypertension: the PRIMUS study

BACKGROUND

Tight blood pressure (BP) control is required to reduce cardiovascular morbidity and mortality.

OBJECTIVE

To evaluate the efficacy and tolerability of the first line combination perindopril/indapamide in hypertension in daily practice.

DESIGN AND METHODS

In this prospective, open-label, observational trial, 1892 general practitioners in Germany recruited patients with hypertension (n = 8023; mean age 59.6 years, 48.1% males, body mass index 27.6 kg/m2, systolic BP >or= 140 mmHg and/or diastolic BP >or= 90 mmHg) between October 2002 and December 2004. Patients received perindopril 2 mg/indapamide 0.625 mg for 12 weeks. BP measured in the general practice setting, safety, and tolerability were evaluated after 4 and 12 weeks.

RESULTS

At baseline, most patients had moderate to severe hypertension (78%); initial BP was 164.6/95.8 mmHg. At inclusion, 38% of the patients were newly diagnosed hypertensives (mean BP 166.1/97.2 mmHg) and 58% of patients had uncontrolled BP despite preexisting antihypertensive treatment (163.5/94.9 mmHg). Previous treatment consisted of beta-blockers (49.5%), ACE inhibitors (36.4%), calcium-antagonists (29.3%), diuretics (28.8%), AT-I receptor antagonists (7.1%), and other treatments (8.1%). In the entire study cohort, treatment with perindopril/indapamide significantly decreased systolic BP (27.9 mmHg), diastolic BP (13.7 mmHg), and pulse pressure (14.2 mmHg), compared with baseline (p < 0.0001); 96% of patients responded to treatment and in 50% of patients BP was normalized (< 140/90 mmHg). Treatment dose was doubled in 9.5% of patients. Similar results were found in various subgroup analyses (newly diagnosed patients, the elderly, and patients with isolated systolic hypertension, additional cardiovascular risk factors, associated diseases, or target organ damage). The most frequent adverse events (< 1% of patients) were dry cough and nausea.

CONCLUSIONS

The open-label, observational study PRIMUS, extends the existing evidence that the first line combination treatment of hypertension with perindopril/indapamide is effective, safe, and well tolerated in a representative cross-section of patients with newly diagnosed or pretreated but uncontrolled hypertension in daily practice.

Treating stage 2 hypertension

The prevalence of hypertension increases with advancing age, due primarily to increases in systolic blood pressure. Systolic hypertension is the most common form of hypertension in individuals over 50 years of age and reflects pathologic decreases in arterial compliance. Systolic blood pressure elevation is a more important risk factor for cardiovascular disease than is diastolic blood pressure elevation. Stage 2 hypertension, defined as blood pressure > or =160/100 mm Hg, is often found in older persons, who are at highest risk for cardiovascular events. In this clinical review, hypertension experts utilize a case study to provide a paradigm for treating older patients with stage 2 hypertension.

Hypertension in black patients: Special issues and considerations

The excess risk for hypertension in black Americans continues to be a major health concern. Although there is considerable information regarding these disease trends, many of the major underpinnings of the etiology of hypertension remain unclear. The excess mortality in blacks due to heart disease, renal failure, and stroke is clearly directly related to the excess burden of hypertension. Amid the recent findings about the pathophysiology of hypertension, some clear differences in the effects of overweight, salt sensitivity, and vascular biology emerge along ethnic lines. These differences may shed some light on the development of more effective treatment strategies. Based on our current knowledge, aggressive management of hypertension in blacks is critical. This review highlights what is known about various factors affecting hypertension and its treatment in black Americans.

Hypertension in black patients: special issues and considerations

The excess risk of hypertension in black Americans continues to be a major health concern. Although there is considerable information regarding these disease trends, much of the major underpinnings of the etiology of hypertension remain unclear. The excess mortality in blacks due to heart disease, renal failure, and stroke are clearly directly related to the excess burden of hypertension. Amid the recent findings about the pathophysiology of hypertension, some clear differences in the effects of overweight, salt sensitivity, and vascular biology emerge along ethnic lines. These differences may shed some light on the development of more effective treatment strategies. Based on our current knowledge, aggressive management of hypertension in blacks is critical. This review highlights what is known about various factors affecting hypertension and its treatment in black Americans.

Drug treatment of essential hypertension: the case for initial combination therapy

Essential hypertension is a major cause of cardiovascular morbidity and mortality in the Western world, yet it remains poorly controlled. Single drug-antihypertensive therapy is unsuccessful in up to half of all patients with hypertension; although lack of adherence may account for a proportion of this, there is evidence of considerable variation in the response of different hypertensive patients to different drug classes. A number of algorithms have been proposed in the literature, with a view to predicting an individual's response to different antihypertensive agents. However, even using such algorithms, hypertension control remains problematic, and they are frequently difficult to apply in everyday clinical practice. Initiation of treatment with low-dose combination antihypertensive therapy, using a drug which reduces total body sodium and/or volume in combination with a drug which blocks the renin-angiotensin system, provides an effective and easily applicable means to improve hypertension control in the primary care setting.

Rationale for fixed-dose combinations in the treatment of hypertension: the cycle repeats

Single-drug therapy remains the preferred way to begin treatment of hypertension, although in many patients this is unable to bring blood pressure (BP) to goal levels. Single-drug therapy, even when maximally titrated, is at best only modestly effective in normalising BP in Stage-I or II hypertension, which represents the majority of the hypertensive population. It is increasingly appreciated that the elusive goal of a 'normal' BP is achieved only if multi-drug therapy is employed. This is especially so when considered in the context of today's lower BP goals. The options for multi-drug therapy are quite simple: either fixed-dose combination therapy or drugs added sequentially one after another to then arrive at an effective multi-drug regimen. Advocates exist for both approaches. A considerable legacy, dating to the 1950's, exists for fixed-dose combination therapies. The rationale to this approach has remained constant. Fixed-dose combination therapy successfully reduces BP because two drugs, each typically working at a separate site, block different effector pathways. In addition, the second drug of such two-drug combinations may check counter-regulatory system activity triggered by the other. For example, a diuretic and beta-blocker combination may find the diuretic correcting the salt-and-water retention which occasionally accompanies beta-blocker therapy. The pattern of adverse effects also differs with fixed-dose combination therapy, in part, because less drug is generally being given. In addition, one component of a fixed-dose combination therapy can effectively counterbalance the tendency of the other to produce adverse effects. For example, the peripheral oedema, that accompanies calcium channel antagonist therapy, occurs less frequently when an ACE inhibitor is co-administered. ACE inhibitors improve, if not eliminate, the peripheral oedema associated with calcium channel antagonists because of their proven ability to cause venodilation. In addition, diuretic therapy-induced volume contraction may generate a state of secondary hyperaldosteronism and thereby electrolyte abnormalities such as hypokalaemia and/or hypomagnesaemia. In many cases, the co-administration of either an ACE inhibitor or an angiotensin II receptor blocker with a diuretic corrects the aforementioned electrolyte disturbances. Fixed-dose combination therapy has a proven record of reducing BP. This form of treatment has been available for close to a half-century. Over that period of time, many physicians have taken advantage of this therapeutic approach even when academic opinion was less than charitable to this concept. Academic opinion is rarely immutable and occasionally irrelevant to prescription practice. Prescription practice is driven by many considerations including ease of use, cost and tolerance of a therapy. Most importantly, the therapeutic pathway taken should successfully result in goal BP being reached in a large number of those treated. Unfortunately, despite the simplicity of the concept behind fixed-dose combination therapy, its success will ultimately rest on cost. If made truly cost-competitive, it will gain an increasing share of the hypertensive market. If not, market forces will relegate it to a secondary role for hypertension treatment.

Combination drug therapy in hypertension: a rational approach for the pharmacist

OBJECTIVE

To review the use of combination therapy versus monotherapy in hypertension, and to review seven major antihypertensive combinations in regard to their pharmacologic actions and appropriateness.

DATA SOURCES

Literature was identified through a MEDLINE search from January 1985 to December 1997. Search terms included hypertension, blood pressure, combination therapy, diuretics, beta-receptor antagonists, calcium channel antagonists, angiotensin-converting enzyme inhibitors (ACEIs). Major hypertension texts were also reviewed for information on combination therapy.

STUDY SELECTION

Clinical studies focusing primarily on blood pressure control with combinations of antihypertensive medications.

DATA EXTRACTION

Data were evaluated with respect to study design, clinical outcomes, and use of antihypertensive classes commonly seen in practice.

DATA SYNTHESIS

Combination therapy in hypertension is often required because many patients cannot be controlled on one drug alone. Available data demonstrate that ACEIs plus diuretics or calcium channel blockers (CCBs) produce synergistic effects on blood pressure. Beta-blockers plus diuretics or CCBs produce additive effects, as does the rarer combination of diltiazem plus a dihydropyridine CCB. Ineffective combinations include beta-blockers plus ACEIs and dihydropyridine CCBs plus diuretics, although there are specific clinical circumstances where these combinations may be used.

CONCLUSION

When used appropriately, certain combinations of antihypertensives can effectively control blood pressure and minimize side effects. The pharmacist who understands and applies the pharmacology of these antihypertensives can help prescribers make rational decisions in selecting combination therapy.