Design of the cardiac insufficiency bisoprolol study II (OBIS II)

Pharmacological interventions for heart failure in people with chronic kidney disease

BACKGROUND

Approximately half of people with heart failure have chronic kidney disease (CKD). Pharmacological interventions for heart failure in people with CKD have the potential to reduce death (any cause) or hospitalisations for decompensated heart failure. However, these interventions are of uncertain benefit and may increase the risk of harm, such as hypotension and electrolyte abnormalities, in those with CKD.

OBJECTIVES

This review aims to look at the benefits and harms of pharmacological interventions for HF (i.e., antihypertensive agents, inotropes, and agents that may improve the heart performance indirectly) in people with HF and CKD.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies through 12 September 2019 in consultation with an Information Specialist and using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

We included randomised controlled trials of any pharmacological intervention for acute or chronic heart failure, among people of any age with chronic kidney disease of at least three months duration.

DATA COLLECTION AND ANALYSIS

Two authors independently screened the records to identify eligible studies and extracted data on the following dichotomous outcomes: death, hospitalisations, worsening heart failure, worsening kidney function, hyperkalaemia, and hypotension. We used random effects meta-analysis to estimate treatment effects, which we expressed as a risk ratio (RR) with 95% confidence intervals (CI). We assessed the risk of bias using the Cochrane tool. We applied the GRADE methodology to rate the certainty of evidence.

MAIN RESULTS

One hundred and twelve studies met our selection criteria: 15 were studies of adults with CKD; 16 studies were conducted in the general population but provided subgroup data for people with CKD; and 81 studies included individuals with CKD, however, data for this subgroup were not provided. The risk of bias in all 112 studies was frequently high or unclear. Of the 31 studies (23,762 participants) with data on CKD patients, follow-up ranged from three months to five years, and study size ranged from 16 to 2916 participants. In total, 26 studies (19,612 participants) reported disaggregated and extractable data on at least one outcome of interest for our review and were included in our meta-analyses. In acute heart failure, the effects of adenosine A1-receptor antagonists, dopamine, nesiritide, or serelaxin on death, hospitalisations, worsening heart failure or kidney function, hyperkalaemia, hypotension or quality of life were uncertain due to sparse data or were not reported. In chronic heart failure, the effects of angiotensin-converting enzyme inhibitors (ACEi) or angiotensin receptor blockers (ARB) (4 studies, 5003 participants: RR 0.85, 95% CI 0.70 to 1.02; I2 = 78%; low certainty evidence), aldosterone antagonists (2 studies, 34 participants: RR 0.61 95% CI 0.06 to 6.59; very low certainty evidence), and vasopressin receptor antagonists (RR 1.26, 95% CI 0.55 to 2.89; 2 studies, 1840 participants; low certainty evidence) on death (any cause) were uncertain. Treatment with beta-blockers may reduce the risk of death (any cause) (4 studies, 3136 participants: RR 0.69, 95% CI 0.60 to 0.79; I2 = 0%; moderate certainty evidence). Treatment with ACEi or ARB (2 studies, 1368 participants: RR 0.90, 95% CI 0.43 to 1.90; I2 = 97%; very low certainty evidence) had uncertain effects on hospitalisation for heart failure, as treatment estimates were consistent with either benefit or harm. Treatment with beta-blockers may decrease hospitalisation for heart failure (3 studies, 2287 participants: RR 0.67, 95% CI 0.43 to 1.05; I2 = 87%; low certainty evidence). Aldosterone antagonists may increase the risk of hyperkalaemia compared to placebo or no treatment (3 studies, 826 participants: RR 2.91, 95% CI 2.03 to 4.17; I2 = 0%; low certainty evidence). Renin inhibitors had uncertain risks of hyperkalaemia (2 studies, 142 participants: RR 0.86, 95% CI 0.49 to 1.49; I2 = 0%; very low certainty). We were unable to estimate whether treatment with sinus node inhibitors affects the risk of hyperkalaemia, as there were few studies and meta-analysis was not possible. Hyperkalaemia was not reported for the CKD subgroup in studies investigating other therapies. The effects of ACEi or ARB, or aldosterone antagonists on worsening heart failure or kidney function, hypotension, or quality of life were uncertain due to sparse data or were not reported. Effects of anti-arrhythmic agents, digoxin, phosphodiesterase inhibitors, renin inhibitors, sinus node inhibitors, vasodilators, and vasopressin receptor antagonists were very uncertain due to the paucity of studies.

AUTHORS' CONCLUSIONS

The effects of pharmacological interventions for heart failure in people with CKD are uncertain and there is insufficient evidence to inform clinical practice. Study data for treatment outcomes in patients with heart failure and CKD are sparse despite the potential impact of kidney impairment on the benefits and harms of treatment. Future research aimed at analysing existing data in general population HF studies to explore the effect in subgroups of patients with CKD, considering stage of disease, may yield valuable insights for the management of people with HF and CKD.

The Impact of Treatment with Beta-Blockers upon Mortality in Chronic Heart Failure Patients

BACKGROUND:

Besides the conventional therapy for heart failure, the diuretics, cardiac glycosides and ACE-inhibitors, current pharmacotherapy includes beta-blockers, mainly because of their pathophysiological mechanisms upon heart remodeling.

AIM:

The study objective was to assess the cardiovascular mortality in the beta-blocker therapy group and to correlate it with the mortality in the control group as well as to correlate the combined outcome of death and/or hospitalization for cardiovascular reason between the two groups.

MATERIALS AND METHODS:

The study included 113 chronic heart failure patients followed up for a period of 18 months. The therapy group received conventional therapy plus the target dose of beta blockers, and the control group received the conventional therapy only. The therapy group was divided in three separate subgroups in terms of the type of beta-blocker (Metoprolol subgroup, Bisoprolol and Carvedilol subgroup). To compare the mortality and the combined outcome, the RRR (relative risk reduction) and NNT (number needed to treat) were used, as well as the survival analysis by Kaplan-Meier.

RESULTS:

The results showed the following: in regards of the cardiovascular mortality, the relative risk for death in the therapy group was 34%, which, though statistically not significant, is of great clinical significance. In regards of the combined outcome (death and/or number of hospitalizations) the results showed a RRR of 40% in the therapy group compared to the control group, which is statistically highly significant.

CONCLUSION:

The study confirmed that patients with stable chronic heart failure, treated with optimal doses of beta-blockers, show a significant reduction of the risk from death as well as combined outcome (death and/or number of hospitalizations).

Evaluation of the functional status questionnaire in heart failure: a sub-study of the second cardiac insufficiency bisoprolol survival study (CIBIS-II)

AIMS

We evaluated a generic quality of life (QoL) Functional Status Questionnaire (FSQ), in patients with chronic heart failure (CHF). The FSQ assesses the 3 main dimensions of QoL: physical functioning, mental health and social role. It also includes 6 single item questions about: work status, frequency of social interactions, satisfaction with sexual relationships, days in bed, days with restricted activity and overall satisfaction with health status. The FSQ was compared to the Minnesota Living with Heart Failure questionnaire (MLwHF).

METHODS AND RESULTS

The FSQ was evaluated in a substudy (n = 340) of the second Cardiac Insufficiency Bisoprolol Survival study (CIBIS-II), a placebo-controlled mortality trial. 265 patients (75%) patients completed both questionnaires at 6 months of follow-up. Both questionnaires indicated substantially impaired QoL. The FSQ demonstrated high internal consistency (Cronbach's α > 0.7 for all items except "social activity" = 0.66) and construct and concurrent validity. After 6 months, the only item on either questionnaire to show a difference between the placebo- and bisoprolol-treatment groups was the single item FSQ question about "days in bed" (p = 0.018 in favour of bisoprolol).

CONCLUSIONS

The FSQ performed well in this study, provided additional information to the MLwHF questionnaire and allowed interesting comparisons with other chronic medical conditions. The FSQ may be a useful general QoL instrument for studies in CHF.

Pharmacogenetics in heart failure: how it will shape the future

Pharmacogenomics is a growing field of research that focuses on how an individual's genetic background influences his or her response to therapy with a drug or device. Increasing evidence from clinical trials in patients with heart failure (HF) due to systolic dysfunction suggests that genetic variations can predict the occurrence of HF, influence the effects of standard therapies, and influence outcomes of HF patients. This article reviews the underlying principles of pharmacogenomics, discusses some of the complex variables that influence the investigational approach to pharmacogenomics, demonstrates how variations in genes encoding a variety of different proteins can influence the effects of pharmacologic agents, and describes the potential impact of pharmacogenomics on the treatment of patients with HF.

Pharmacologic therapy of chronic heart failure

Over the past 2 decades, investigators have learned more about the pathophysiologic changes that occur in systolic and diastolic dysfunction. Ironically, in some cases, the biologic pathways that have protected the heart during acute dysfunction are the same pathways that cause progressive deleterious effects with chronic activation. In particular, it is the activation of the neurohormonal system that has a significant impact on disease progression. As a result, the neurohormonal system has provided a key target for pharmacologic therapy in patients with heart failure secondary to systolic dysfunction. These targets include the renin-angiotensin-aldosterone system as well as the sympathetic nervous system. Neurohormonal manipulation, however, is often ineffective in the pharmacologic therapy of patients with endstage heart failure, therefore other treatment strategies - including the use of inotropic agents to improve pump function and diuretics to control fluid balance are needed.

Beta-blocker benefit according to severity of heart failure

BACKGROUND AND AIMS

Beta-blockers are an established treatment for chronic heart failure. However, the relationship between their benefit and the severity of the disease remains to be determined.

METHODS AND RESULTS

We studied the relationship between amplitude of benefit of beta-blockers and severity of chronic heart failure, based on data for mortality and hospitalizations for worsening heart failure, using a meta-analysis of randomized controlled trials, complementary subgroup analyses and analysis of individual data from the CIBIS II trial. In the meta-analysis, mortality was reduced by 22% (95%CI: 16 to 28) and hospitalizations for worsening heart failure by 24% (95%CI: 20 to 29). Benefit was similar with metoprolol, bisoprolol and carvedilol. After exclusion of bucindolol trials, due to the heterogeneity of results for mortality, the reduction in mortality was similar according to the severity of heart failure, assessed either by left ventricular ejection fraction or by New York Heart Association classification. In CIBIS II, beta-blockers induced a significant reduction in mortality of 45% (95%CI: 9 to 66), 41% (95%CI: 17 to 59) and 23% (95%CI: 1 to 40) in the low, intermediate and high risk groups, respectively. Hospitalizations were reduced by 35% (95%CI: 2 to 57), 41% (95%CI: 18 to 58) and 23% (95%CI: 0 to 41), there was no significant difference between the three score groups.

CONCLUSION

We conclude that the amplitude of benefit of the beta-blockers carvedilol, metoprolol and bisoprolol on mortality and morbidity is similar, regardless of the severity of chronic heart failure.

Bisoprolol for the treatment of chronic heart failure: a meta-analysis on individual data of two placebo-controlled studies--CIBIS and CIBIS II. Cardiac Insufficiency Bisoprolol Study

BACKGROUND

Despite the available evidence from randomized clinical trials, beta-blockers are often not used optimally in patients with congestive heart failure (CHF). This meta-analysis aims at providing a precise and quantitative estimate of the benefit and risks of long-term bisoprolol on major clinical events in patients with CHF, both overall and in selected subgroups. This may help clinicians in their decisions as to whether to prescribe bisoprolol for their individual patients.

METHODS

Meta-analysis was performed of results from the 2 randomized, controlled clinical studies in which bisoprolol was compared with placebo (Cardiac Insufficiency Bisoprolol Study [CIBIS and CIBIS II]), which included 3288 patients with proven CHF. The main outcomes were total death, cardiovascular death, sudden death, hospitalization for heart failure, and myocardial infarction.

RESULTS

A highly significant 29.3% relative reduction of death (17%, 40%; P =.00003) was observed, as well as significant risk reduction in cardiovascular death and sudden death in favor of bisoprolol. Also, a highly significant relative reduction of 18.4% (25%, 11%; P =.00001) in hospital admission or death was observed. A similar relative reduction of death was consistently observed in selected subgroups of patients.

CONCLUSIONS

Bisoprolol prevents major cardiovascular events in patients with CHF with a high benefit-to-risk ratio and can be recommended for these patients.

Beta-adrenergic blocker mortality trials in congestive heart failure

Many of the current discussions of beta-adrenergic blocker therapy in patients with congestive heart failure have used fairy tales to describe the evolution of this treatment from contraindication to standard of care. This article reviews the early studies that initiated this revolution in heart failure therapy and discusses the major mortality trials that have demonstrated that these agents improve survival and limit the progression of congestive heart failure. These major trials have used 1 of 4 beta blockers (metoprolol, bisoprolol, carvedilol, or bucindolol) in varying study designs with different patient populations. Each trial had different objectives and limitations, and these are described in the context of their impact on proving a survival benefit. In addition, the specific effect of beta-blocker therapy on sudden death in patients with heart failure is briefly discussed. The weight of these trials suggests that beta-adrenergic blocker therapy can save 1 life of every 35 patients treated in patients with mild-to-moderate heart failure. The data are compelling and the techniques for "starting low and going slow" with titrations have been well documented.

The carvedilol hibernation reversible ischaemia trial; marker of success (CHRISTMAS). The CHRISTMAS Study Steering Committee and Investigators

BACKGROUND

Carvedilol improves left ventricular (LV) function when heart failure is due to LV systolic dysfunction, but the magnitude of the response is heterogeneous among patients with coronary disease, possibly reflecting the presence or volume of hibernating myocardium.

AIMS

The primary objective of the study is to determine whether the presence of hibernating myocardium predicts the magnitude of improvement in LV ejection fraction in response to carvedilol among patients with heart failure and LV systolic dysfunction due to coronary disease.

METHODS

The study is a prospective, randomised, parallel-group, double-blind, multi-centre study comparing carvedilol and placebo over a period of approximately 6 months in the above patient population. The primary end-point is the comparison of the mean change, from baseline to the final visit, in radionuclide-determined LV ejection fraction among patients on placebo with those on carvedilol stratified according to the presence of hibernating myocardium. Hibernating status will be determined by a combination of echocardiographic and myocardial perfusion (technetium-99m sestamibi) imaging.

RESULTS

255 patients have undergone screening tests of which 207 have been randomised so far. The study intends to randomise 400 patients and the first report of results is expected in 2000.

CONCLUSIONS

As far as we are aware this is the first randomised controlled trial to investigate the effects of treatment in patients stratified according to the presence of hibernating myocardium. The study will provide insights into the prevalence of myocardial hibernation, its natural history, and its influence on prognosis as well as the interaction between the presence of hibernating myocardium and the effects of treatment with carvedilol.

Update of recent clinical trials in heart failure and myocardial infarction

BACKGROUND

There are currently many on-going clinical trials assessing therapies for the treatment of patients with heart failure.

AIMS

The purpose of this series of papers is to present concise summaries of current randomised trials in the field of heart failure and myocardial infarction (MI).

METHODS

Data from large double-blind, placebo-controlled trials, which are on-going or have only recently been published, are given in a format allowing easy comparison. Where appropriate, data from smaller studies are included.

RESULTS

Major studies which are examined in this issue include CIBIS II, MERIT-HF, RESOLVD, SPICE, VEST, MACH-1, ATLAS, RALES, CIDS and CASH. These trials assess the efficacy and safety of beta-blocker, angiotensin-II-receptor blocker, positive inotropic agent, calcium antagonist, angiotensin-converting enzyme (ACE) inhibitor, aldosterone receptor blocker, and antiarrhythmic interventions in the treatment of heart failure.

CONCLUSIONS

The presentation of data from these on-going trials should allow an up-to-date assessment, by physicians, of the most appropriate and effective treatment for patients with heart failure. It is evident that some therapies may play no further role in the treatment of heart failure, due to the increased risk of mortality associated with their administration, whilst others may convey significant benefits.

Etiology and response to drug treatment in heart failure

Clinical trials in heart failure (HF) tend to randomize patients according to demographic characteristics and severity of left ventricular dysfunction, without taking account of the precise diagnosis. This article reviews results from recent trials suggesting that the etiology of HF, and particularly whether it is ischemic or nonischemic, may influence the long-term prognosis and the response to treatment. Some studies, but not all, suggest that nonischemic HF has a better prognosis than ischemic HF. The data on the benefits of angiotensin-converting enzyme inhibitors in ischemic versus nonischemic HF are conflicting. Carvedilol, and recently, bisoprolol have been shown to reduce mortality in ischemic and nonischemic HF, whereas metoprolol has, to date, improved prognosis only in dilated cardiomyopathy. Better responses to digoxin, amlodipine and amiodarone have been reported in non-ischemic HF. There is at present no clear explanation for the apparent therapeutic differences between ischemic and nonischemic HF. Absence of a rigorous definition of "nonischemic HF" in many studies makes interpretation of the results difficult. Further studies to clarify the effects of etiology of HF on the response to treatment could be particularly important for preventing progression to more advanced stages, in which any type of drug therapy may have limited value in prolonging survival. An individualized therapeutic approach, based on etiology of HF and possibly other factors such as plasma drug levels or the levels of neurohormones, could result in major progress in treating HF patients.

Medical therapy of chronic heart failure. Role of ACE inhibitors and beta-blockers

Heart failure has long been considered to have a progressive downhill course leading inexorably to an early demise. This course often occurs silently, in the absence of any obvious cardiac insults. The reason for this is a combination of cell loss, myocyte dysfunction, impaired energetics, and pathologic remodeling of the chamber. Improved clinical outcome should result from strategies that reduce the biologic signals responsible for myocyte growth, dysfunction, and loss and chamber remodeling. Clinicians should no longer attempt to treat chronic heart failure with pharmacologic growth and remodeling process. In time, it may be possible for the clinician to view the treatment of heart failure largely as a matter of improving the biologic function of the myocardium.

The sympathetic nervous system in chronic heart failure

The sympathetic nervous system plays a pivotal role in the natural history of chronic heart failure (CHF). There is early activation of cardiac adrenergic drive, which is followed by an increasing magnitude of generalized sympathetic activation, with worsening heart failure. The adverse consequences predominate over the short-term compensatory effects and are mediated through downregulation of beta-receptor function and harmful biological effects on the cardiomyocyte. beta-blockers exert a beneficial effect on the natural history of CHF by attenuating the negative biological effects, restoring homogeneity of contractile/relaxant mechanisms, and reducing the risk of myocardial ischemia and arrhythmias. After pioneering work conducted over 20 years ago, numerous studies have shown the beneficial effects of beta-blockade on left ventricular function, and survival, morbidity, and mortality rates in CHF. Large-scale trials are underway to determine the overall benefits of beta-blockade in heart failure.

Over 20 years' experience of beta-blockade in heart failure

The use of beta-blocker therapy in heart failure was contraindicated for many years because it was considered to block necessary sympathetic compensatory responses to reduced cardiac function. However, early studies provided promising results in terms of improved symptoms and work capacity and reduced heart size. Small-scale studies have been completed over the past 20 years but until large-scale, long-term, randomized trials were conducted, the potential of beta-blockers in heart failure was not confirmed. The results of randomized trials published to date have included over 3,000 patients and the results show improvements in left ventricular function and heart rate. Significant improvements in New York Heart Association classification were also shown. Although no conclusive effect on mortality was shown, the first Cardiac Insufficiency Bisoprolol Study (CIBIS) indicated a trend toward improved survival during long-term treatment with bisoprolol. Ongoing studies have been specifically designed to investigate the effects of beta-blockers on survival. One of these trials, CIBIS II, which was terminated early in 1998 because of a positive effect on survival, is expected to report in late summer 1998. Such trials will also examine the different mechanisms of action of beta-blockers in heart failure and the influence of causes on the effects of beta-blockade.