Controversies surrounding the use of beta-blockers in older patients with cardiovascular disease

Effect of age on the use of evidence-based therapies for acute myocardial infarction

BACKGROUND

Previous studies have documented an underuse of evidence-based therapies in patients with acute myocardial infarction (AMI). However, many of these studies failed to consider contraindications to therapy, the effect of age (ie, elderly vs non-elderly patients) on use, or both. The objective of this study was to determine whether elderly patients are less likely than non-elderly patients to receive evidence-based AMI treatments, both before and after the consideration of contraindications to therapy.

METHODS

A retrospective chart review of a random sample of 5131 patients with AMI who were admitted to 1 of 44 hospitals in Ontario was conducted for the fiscal years 1994 to 1996. Using the Canadian Cardiovascular Research Team (CCORT)/Canadian Cardiovascular Society (CCS) Quality Indicators for AMI Care, we classified patients as being eligible or ideal (ie, no contraindications to treatment) candidates to receive aspirin, beta-blockers, thrombolysis, angiotensin-converting enzyme inhibitors (ACEIs), or statins or to undergo lipid profiling. The proportions of eligible and ideal patients who received treatment were calculated, and the latter were compared with benchmarks.

RESULTS

The median age of the cohort was 69 years; 63% were of the patients were aged > or =65 years. There was underperformance of prescribing treatments in ideal candidates relative to benchmarks (eg, aspirin at discharge: 78.6% vs 90% benchmark). The odds of ideal (ie, no contraindications) elderly candidates receiving various evidence-based AMI treatments were consistently less than that of non-elderly patients with AMI, with the exception of ACEIs at discharge (odds ratio, 1.46; 95% CI, 1.22-1.74).

CONCLUSIONS

Despite adjustments for contraindications to therapy, the underuse of AMI treatments, particularly in elderly patients, was found.

Extended-release metoprolol succinate in chronic heart failure

OBJECTIVE

To review the pharmacology, pharmacokinetics, efficacy, and tolerability of extended-release (ER) metoprolol succinate and its role in the management of chronic heart failure.

DATA SOURCES

A MEDLINE search of English-language literature (1990-October 2002) was conducted using congestive heart failure and metoprolol CR/XL or metoprolol CR/ZOK as search terms to identify pertinent studies.

STUDY SELECTION/DATA EXTRACTION

All of the articles identified from the data sources were evaluated, with priority given to randomized, double-blind, placebo-controlled studies.

DATA SYNTHESIS

ER metoprolol succinate is a controlled-release tablet designed to produce even and consistent beta(1)-blockade throughout the 24-hour dosing interval, with less fluctuation in metoprolol plasma concentrations compared with immediate-release metoprolol. Three randomized, double-blind, placebo-controlled trials have evaluated the efficacy of ER metoprolol succinate in the treatment of patients with chronic heart failure. The MERIT-HF (Metoprolol CR/XL Randomized Intervention Trial in Congestive Heart Failure) study, the largest of these trials and the largest randomized mortality trial with beta-blockers in heart failure to date, demonstrated that ER metoprolol succinate reduced the relative risk of all-cause mortality by 34% versus placebo. Furthermore, the relative risk of the combined endpoint of mortality plus all-cause hospitalizations was reduced by 19% and sudden death was reduced by 41%. The benefits of therapy were evident in various patient subgroups, including elderly patients and those with diabetes mellitus. ER metoprolol succinate was generally well tolerated, with a similar proportion of patients discontinuing therapy due to adverse events relative to placebo (9.8% and 11.7%, respectively).

CONCLUSIONS

ER metoprolol succinate therapy provides substantial mortality and morbidity benefits in patients with New York Heart Association class II and III heart failure who are stabilized on angiotensin-converting enzyme inhibitors and diuretics. ER metoprolol succinate is administered once daily, is well tolerated, and provides consistent beta(1)-blockade over the 24-hour dosing interval.

Titration of beta-blockers in heart failure. How to maximize benefit while minimizing adverse events

Data from large clinical trials indicate that beta-blocker therapy can be successfully initiated and adjusted upward in most patients with stable chronic heart failure who already take standard heart failure therapy. Such therapy typically includes ACE inhibitors, diuretics, and digoxin. With optimal titration and maintenance strategies, beta-blockers are effective and well tolerated in these patients. It is recommened that all patients with clinically stable mild to moderate chronic heart failure (NYHA class II or III), no contraindications to beta-blocker use, and an LVEF less than 40% should be treated with beta-blockers. Based on the results of recent clinical trials on heart failure, beta-blocker therapy should be initiated at a low dose and slowly tirtrated upward as tolerated. A patient's heart failure should be stable for at least 2 weeks before the dose is adjusted upward. Slow titration facilitates maximal tolerability. In primary care practice, physicians should apply titration strategies and target dosed that have been demonstrated to reduce morbidity and mortality in clinical trials. Although worsening heart failure or other adverse events occur in a minority of patients who take beta-blockers, these effects can be managed by adjusting the dose of ACE inhibitor or diuretic, or both, or by temporarily withholding the beta-clocker. Currently, professional treatment guidelines recommend beta-blocker therapy in combination with ACE inhibitors an diuretics as the standard of care in the treatment of heart failure.

Quality of ambulatory care after myocardial infarction among Medicare patients by type of insurance and region

PURPOSE

To evaluate use of effective cardiac medications and rehabilitation after myocardial infarction in the ambulatory setting in health maintenance organizations (HMOs) and fee-for-service care, and by region.

SUBJECTS AND METHODS

We surveyed elderly Medicare patients during 1996 and 1997 in California (n = 516), Florida (n = 304), and the Northeast (n = 220; Massachusetts, New York, and Pennsylvania) approximately 18 months after myocardial infarction. We assessed use of cardiac medications and rehabilitation for HMO (n = 520) and fee-for-service (n = 520) patients matched by age, sex, month of infarct, and region.

RESULTS

Across all regions, similar proportions of HMO and fee-for-service patients were using aspirin (72%, n = 374 vs. 74%, n = 387), beta-blockers (38%, n = 195 vs. 32%, n = 168), angiotensin-converting enzyme inhibitors (31%, n = 159 vs. 29%, n = 148), cholesterol-lowering agents (28%, n = 146 vs. 30%, n = 157), and calcium channel blockers (31%, n = 162 vs. 31%, n = 159; all P >0.07), except in California where more HMO patients received beta-blockers (36%, n = 93 vs. 26%, n = 66, P = 0.01). In adjusted analyses, use of these drugs did not differ significantly between HMO and fee-for-service patients. Substantial regional differences were evident in the use of beta-blockers (Northeast 46%, n = 102; Florida 34%, n = 102; California 31%, n = 159) and cholesterol-lowering agents (California 35%, n = 182; Florida 24%, n = 73; Northeast 22%, n = 48; each P <0.001). Fee-for-service patients were more likely than HMO patients to receive cardiac rehabilitation in unadjusted (32%, n = 167, vs. 22%, n = 141, P = 0.001) and adjusted analyses.

CONCLUSIONS

Both HMO and fee-for-service patients would likely benefit from greater use of beta-blockers and cholesterol-lowering agents. Professional fees for cardiac rehabilitation may promote increased use among fee-for-service patients. Future studies should assess the quality of ambulatory cardiac care in different types of HMOs and the reasons for geographic variations in cardiac drug use.

Beta-blockers for congestive heart failure: what is the current consensus?

Despite the availability of angiotensin converting enzyme (ACE) inhibitors for patients with congestive heart failure (CHF), mortality and morbidity remains unacceptably high. CHF is thought to progress as a result of activation of endogenous neurohormonal systems which are activated by the initial myocardial injury. The 2 neurohormonal systems which seem to be important in CHF are the sympathetic nervous system (SNS), and the renin-angiotensin-aldosterone system (RAAS). While stimulation of the SNS has important circulatory support functions in the short term, long term activation appears to have deleterious effects on cardiac function and outcomes. The purpose of this article is to review the literature on the use of beta-blockers in patients with CHF. The published randomised clinical trials of beta-blockers in patients with CHF have shown very promising effects on mortality and morbidity. Several systematic overviews of these trials also suggest beneficial effects on mortality, hospitalisation for CHFE need for transplant, and ejection fraction. The effect of beta-blockers on exercise tolerance. New York Heart Association Function Class (NYHA-FC) and quality of life remain equivocal. The recent presentation of the results from several large-scale trials which were terminated early because of significant survival benefit, has removed any concern over the robustness of the mortality data. Available evidence suggests that a wide variety of patients with CHF, including the elderly, should be considered for beta-blocker therapy. Caution is warranted in the initiation and titration of therapy, as symptoms of CHF may transiently worsen. Whether all beta-blockers are equally efficacious remains unknown.

Coronary artery disease in the geriatric population

The elderly represent an increasingly important and challenging subset of the population of patients with ischemic heart disease. They are more likely to have comorbid conditions, atypical presentations, and unfavorable outcomes than their younger counterparts. Some of these findings are undoubtedly related to the structural and functional changes in the cardiovascular system associated with aging. The available data suggest that standard pharmacologic, thrombolytic, and definitive revascularization techniques have important roles in the therapy of geriatric patients but have been underused.