Withdrawal of digoxin from patients with chronic heart failure treated with angiotensin-converting-enzyme inhibitors. RADIANCE Study

Outcomes of a contemporary sample of patients with atrial fibrillation taking digoxin: results from the AFBAR study

INTRODUCTION AND OBJECTIVES

We aimed to assess and compare the effect of digoxin on clinical outcomes in patients with atrial fibrillation vs those under beta-blockers or none of these drugs.

METHODS

AFBAR is a prospective registry study carried out by a team of primary care physicians (n=777 patients). Primary endpoints were survival, survival free of admission due to any cause, and survival free of admission due to cardiovascular causes. The mean follow up was 2.9 years. Four groups were analyzed: patients receiving digoxin, beta-blockers, or digoxin plus beta-blockers, and patients receiving none of these drugs.

RESULTS

Overall, 212 patients (27.28%) received digoxin as the only heart control strategy, 184 received beta-blockers (23.68%), 58 (7.46%) were administered both, and 323 (41.57%) received none of these drugs. Digoxin was not associated with all-cause mortality (estimated hazard ratio=1.42; 95% confidence interval, 0.77-2.60; P=.2), admission due to any cause (estimated hazard ratio=1.03; 95% confidence interval, 0.710-1.498; P=.8), or admission due to cardiovascular causes (estimated hazard ratio=1.193; 95% confidence interval, 0.725-1.965; P=.4). No association was found between digoxin use and all-cause mortality, admission due to any cause, or admission due to cardiovascular causes in patients without heart failure. There was no interaction between digoxin use and sex in all-cause mortality or in survival free of admission due to any cause. However, an association was found between sex and admission due to cardiovascular causes.

CONCLUSIONS

Digoxin was not associated with increased all-cause mortality, survival free of admission due to any cause, or admission due to cardiovascular causes, regardless of underlying heart failure.

The previous use of digoxin does not worsen early outcome of acute coronary syndromes: an analysis of the ARIAM Registry

The aim of the study was to determine the influence of the previous use of digoxin on the hospital mortality and complications of patients admitted because of acute coronary syndrome (ACS). We analyzed the data of patients included in the ARIAM-Andalucia Registry, which involves 49 hospitals in Andalucia, Spain, from 2007 to 2012. Patients on digoxin treatment prior to their admission because of ACS constituted the digoxin group (DG), and were compared with the group of patients not on digoxin. Logistic regression and propensity score matching were used to analyze the differences. We included 20,331 patients, of whom 244 (1.2%) were on digoxin. DG patients were older (73.1 vs 63.7 years old), more often women, and had more diabetes, hypertension, previous myocardial infarction, heart failure, stroke, atrial fibrillation, peripheral vascular disease, obstructive pulmonary disease or kidney disease. On univariate analysis, DG patients had significantly higher hospital mortality (13.5 vs 5.3% P < 0.001), and more cardiogenic shock, but less ventricular fibrillation, and no differences in atrioventricular block, stroke or reinfarction. After the multivariate analysis, DG had no significant influence on hospital prognosis [odds ratio (OR) 1.21, 95% confidence interval 0.79-1.86]. The analysis of a propensity-matched cohort of 464 patients (232 DG and 232 NoDG) did not find differences in hospital mortality (13.4 vs 13.4%) nor other complications. In our cohort of ACS patients, the previous treatment with digoxin was not associated with an increase in dysrhythmic complications nor was an independent predictor of mortality during hospitalization.

Use of a simplified nomogram to individualize digoxin dosing versus standard dosing practices in patients with heart failure

STUDY OBJECTIVES

To compare the frequency of achieving a therapeutic serum digoxin concentration (SDC), defined as 0.5-0.9 ng/ml, by using a simplified nomogram to individualize digoxin dosing with standard dosing practices in patients with heart failure, and to characterize the relationship between genetic polymorphisms of the ABCB1 gene and SDC.

DESIGN

Prospective study with a historical control group.

SETTING

Outpatient care center of an urban academic medical center.

PATIENTS

A total of 131 adults with heart failure due to left ventricular dysfunction who were treated with digoxin.

INTERVENTION

Digoxin doses were determined either by the dosing nomogram (65 patients) or standard care (SC; 66 patients) by using historical controls who were randomly selected from a list of SDCs obtained from laboratory records and who had their digoxin doses determined by standard dosing practices.

MEASUREMENTS AND MAIN RESULTS

The primary end point was the proportion of patients achieving a steady-state SDC of 0.5-0.9 ng/ml; secondary end points were mean SDC and proportion of patients achieving a steady-state SDC lower than 1.0 ng/ml. Postdistributive steady-state SDCs were measured 2-4 weeks after digoxin dosage adjustment or initiation. Therapeutic SDCs were achieved with similar frequency in both groups (38.7% in the nomogram group vs 34.5% in the SC group, p=0.65); however, more patients in the nomogram group had SDCs lower than 1.0 ng/ml than in the SC group (85.0% vs 44.9%, p<0.001). Mean daily digoxin doses were lower in the nomogram group (149 ± 67 μg vs 177 ± 74 μg, p=0.02), resulting in lower mean SDCs compared with those in the SC group (0.52 ± 0.30 ng/ml vs 1.12 ± 0.58 ng/ml, p<0.001). Patients in the pharmacogenetic substudy provided blood samples for genotyping of three common ABCB1 single nucleotide polymorphisms: C1236T (rs1128503), G2677T/A (rs2032582), and C3435T (rs1045642). SDCs were not significantly associated with ABCB1 genotypes.

CONCLUSION

Our simplified digoxin dosing nomogram resulted in lower SDCs compared with standard dosing practices but achieved therapeutic SDCs with similar frequency. A greater proportion of patients dosed according to our nomogram had SDCs lower than 1.0 ng/ml, consistent with consensus guidelines. Genetic polymorphisms of the ABCB1 gene were not associated with SDC.

Outcomes of a contemporary sample of patients with atrial fibrillation taking digoxin: results from the AFBAR study

INTRODUCTION AND OBJECTIVES

We aimed to assess and compare the effect of digoxin on clinical outcomes in patients with atrial fibrillation vs those under beta-blockers or none of these drugs.

METHODS

AFBAR is a prospective registry study carried out by a team of primary care physicians (n=777 patients). Primary endpoints were survival, survival free of admission due to any cause, and survival free of admission due to cardiovascular causes. The mean follow up was 2.9 years. Four groups were analyzed: patients receiving digoxin, beta-blockers, or digoxin plus beta-blockers, and patients receiving none of these drugs.

RESULTS

Overall, 212 patients (27.28%) received digoxin as the only heart control strategy, 184 received beta-blockers (23.68%), 58 (7.46%) were administered both, and 323 (41.57%) received none of these drugs. Digoxin was not associated with all-cause mortality (estimated hazard ratio=1.42; 95% confidence interval, 0.77-2.60; P=.2), admission due to any cause (estimated hazard ratio=1.03; 95% confidence interval, 0.710-1.498; P=.8), or admission due to cardiovascular causes (estimated hazard ratio=1.193; 95% confidence interval, 0.725-1.965; P=.4). No association was found between digoxin use and all-cause mortality, admission due to any cause, or admission due to cardiovascular causes in patients without heart failure. There was no interaction between digoxin use and sex in all-cause mortality or in survival free of admission due to any cause. However, an association was found between sex and admission due to cardiovascular causes.

CONCLUSIONS

Digoxin was not associated with increased all-cause mortality, survival free of admission due to any cause, or admission due to cardiovascular causes, regardless of underlying heart failure.

Digitalis for treatment of heart failure in patients in sinus rhythm

BACKGROUND

Digitalis glycosides have been in clinical use for the treatment of heart failure (HF) for longer than 200 years. In recent years, several trials have been conducted to address concerns about their efficacy and toxicity.

OBJECTIVES

To examine the effectiveness of digitalis glycosides in treating HF in patients with normal sinus rhythm. To examine the effects of digitalis in patients taking diuretics and angiotensin-converting enzyme inhibitors; in patients with varying severity and duration of disease; in patients with prior exposure to digitalis versus no prior exposure; and in patients with "HF due to systolic dysfunction" versus "HF with preserved ejection fraction."

SEARCH METHODS

Searches on the following databases were updated in May 2013: The Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, and Dissertation Abstracts. Annual meeting abstracts of the American Heart Association, the American College of Cardiology, and the European Society of Cardiology were searched from 1996 to March 2013. In addition, reference lists provided by the pharmaceutical industry (GlaxoSmithKline and Covis Pharma) were searched.

SELECTION CRITERIA

Included were randomized placebo-controlled trials of 20 or more adult participants of either sex with symptomatic HF who were studied for seven weeks or longer. Excluded were trials in which the prevalence of atrial fibrillation was 2% or greater, or in which any arrhythmia that might compromise cardiac function or any potentially reversible cause of HF such as acute ischemic heart disease or myocarditis was present.

DATA COLLECTION AND ANALYSIS

Articles selected from the searches described above were evaluated in a joint effort of the review authors. The staff of the Cochrane Heart Group ran searches on the Cochrane Central Register of Controlled Trials, MEDLINE, and EMBASE.

MAIN RESULTS

No new studies were identified in the updated searches. Thirteen studies (7896 participants) are included, and major endpoints of mortality, hospitalization, and clinical status, based respectively on 8, 4, and 12 of these selected studies, were recorded and analyzed. The data show no evidence of a difference in mortality between treatment and control groups, whereas digitalis therapy is associated with lower rates of both hospitalization and clinical deterioration. The largest study, in which most participants were taking angiotensin-converting enzyme inhibitors, showed a significant rise in "other cardiac" deaths, possibly due to arrhythmias. However collectively, these findings were based on studies done before beta-blockers, as well as angiotensin receptor blockers and aldosterone antagonists, became widely used to treat HF.

AUTHORS' CONCLUSIONS

The literature indicates that digitalis may have a useful role in the treatment of patients with HF who are in normal sinus rhythm. New trials are needed to elucidate the importance of the dosage of digitalis and its usefulness in the era of beta-blockers and other agents shown to be effective in treating HF.

Can medications be safely withdrawn in patients with stable chronic heart failure? systematic review and meta-analysis

BACKGROUND

Heart failure (HF) therapy involves use of multiple medications. There is little guidance on the safety and impact on clinical outcomes of stopping HF medications.

METHODS AND RESULTS

A comprehensive systematic search for studies of drug therapy withdrawal in HF was performed. Meta-analysis of the risk ratio (RR) was performed with the use of the Mantel-Haenszel random effects model for all-cause mortality and cardiovascular outcomes. Twenty-six studies met the inclusion criteria. Studies on withdrawal of renin-angiotensin-aldosterone system (RAAS) inhibitors and beta-blockers in HF are scarce and small, yet show relatively convincingly that such withdrawals have untoward effects on cardiac structure, symptoms, and major outcomes. Meta-analysis of 7 studies of digoxin withdrawal (2,987 participants) without background beta-blocker showed increased HF hospitalizations (RR 1.30, 95% confidence interval [CI] 1.16-1.46; P < .0001), but no impact on all-cause mortality (RR 1.00, 95% CI 0.90-1.12; P = .06) nor reduction in all-cause hospitalization (RR 1.03, 95% CI 0.98-1.09; P = .27). Diuretic withdrawal trials demonstrated an ongoing need for these agents in chronic HF. Studies in peripartum cardiomyopathy showed that medications could be successfully withdrawn after recovery.

CONCLUSION

Current evidence discourages any attempt to discontinue RAAS inhibitors or beta-blockers in patients with stable HF, regardless of clinical and/or echocardiographic status. Formal withdrawal trials of other classes are needed.

The use of digoxin in patients with worsening chronic heart failure: reconsidering an old drug to reduce hospital admissions

Digoxin is the oldest cardiac drug still in contemporary use, yet its role in the management of patients with heart failure (HF) remains controversial. A purified cardiac glycoside derived from the foxglove plant, digoxin increases ejection fraction, augments cardiac output, and reduces pulmonary capillary wedge pressure without causing deleterious increases in heart rate or decreases in blood pressure. Moreover, it is also a neurohormonal modulator at low doses. In the pivotal DIG (Digitalis Investigation Group) trial, digoxin therapy was shown to reduce all-cause and HF-specific hospitalizations but had no effect on survival. With the discovery of neurohormonal blockers capable of reducing mortality in HF with reduced ejection fraction, the results of the DIG trial were viewed as neutral, and the use of digoxin declined precipitously. Although modern drug and device-based therapies have dramatically improved the survival of ambulatory patients with HF, outcomes for patients with worsening chronic HF, defined as deteriorating signs and symptoms on standard therapy often leading to unscheduled clinic or emergency department visits or hospitalization, have largely remained unchanged over the past 2 decades. The available data suggest that a therapeutic trial of digoxin may be appropriate in patients with worsening chronic heart failure who remain symptomatic.

Inotropes

Inotropes have been fundamental to resuscitation of acute cardiogenic shock for decades. Heart failure and cardiogenic shock, in severe cases, are syndromes characterized in many patients by a reduction in myocardial contractile force. While inotropes successfully increase cardiac output, their use has been plagued by excessive mortality due to increased tachycardia and myocardial oxygen consumption leading to arrhythmia and myocardial ischemia. There is a pressing need for new inotropic agents that avoid these harmful effects. This review describes the mechanism of action and the clinical utility of some of the older inotropic agents, which are still commonly used, and provides an update for physicians on the development of newer inotropic drugs. The field is rapidly changing, and it is likely that new agents will be designed that improve systolic performance without necessarily increasing the myocardial oxygen consumption.

Digoxin use and lower 30-day all-cause readmission for Medicare beneficiaries hospitalized for heart failure

BACKGROUND

Heart failure is the leading cause for hospital readmission, the reduction of which is a priority under the Affordable Care Act. Digoxin reduces 30-day all-cause hospital admission in chronic systolic heart failure. Whether digoxin is effective in reducing readmission after hospitalization for acute decompensation remains unknown.

METHODS

Of the 5153 Medicare beneficiaries hospitalized for acute heart failure and not receiving digoxin, 1054 (20%) received new discharge prescriptions for digoxin. Propensity scores for digoxin use, estimated for each of the 5153 patients, were used to assemble a matched cohort of 1842 (921 pairs) patients (mean age, 76 years; 56% women; 25% African American) receiving and not receiving digoxin, who were balanced on 55 baseline characteristics.

RESULTS

Thirty-day all-cause readmission occurred in 17% and 22% of matched patients receiving and not receiving digoxin, respectively (hazard ratio [HR] for digoxin, 0.77; 95% confidence interval [CI], 0.63-0.95). This beneficial association was observed only in those with ejection fraction <45% (HR 0.63; 95% CI, 0.47-0.83), but not in those with ejection fraction ≥ 45% (HR 0.91; 95% CI, 0.60-1.37; P for interaction, .145), a difference that persisted throughout the first 12 months postdischarge (P for interaction, .019). HRs (95% CIs) for 12-month heart failure readmission and all-cause mortality were 0.72 (0.61-0.86) and 0.83 (0.70-0.98), respectively.

CONCLUSIONS

In Medicare beneficiaries with systolic heart failure, a discharge prescription of digoxin was associated with lower 30-day all-cause hospital readmission, which was maintained at 12 months, and was not at the expense of higher mortality. Future randomized controlled trials are needed to confirm these findings.

Heart rate: a prognostic factor and therapeutic target in chronic heart failure. The distinct roles of drugs with heart rate-lowering properties

Heart rate not only predicts outcome but may also be a therapeutic target in patients with chronic heart failure. Several classes of pharmacological agents can be used to modulate heart rate, including beta-blockers, ivabradine, digoxin, amiodarone, and verapamil. Choice of agent will depend on heart rhythm, co-morbidities, and disease phenotype. Beneficial and harmful interactions may also exist. The aim of this paper is to summarize the current body of knowledge regarding the relevance of heart rate as a prognostic factor (risk marker) and particularly as a therapeutic target (risk factor) in patients with chronic heart failure, with a special focus on ivabradine, a novel agent that is currently the only available purely bradycardic agent.

Comparison between ivabradine and low-dose digoxin in the therapy of diastolic heart failure with preserved left ventricular systolic function

Multicenter trials have demonstrated that in patients with sinus rhythm ivabradine is effective in the therapy of ischemic heart disease and of impaired left ventricular systolic function. Ivabradine is ineffective in atrial fibrillation. Many patients with symptomatic heart failure have diastolic dysfunction with preserved left ventricular systolic function, and many have asymptomatic paroxysmal atrial fibrillation. Ivabradine is not indicated in these conditions, but it happens that it is erroneously used. Digoxin is now considered an outdated and potentially dangerous drug and while effective in the mentioned conditions, is rarely used. The aim of the study was to compare the therapeutic effects of ivabradine in diastolic heart failure with preserved left ventricular systolic function. Patients were assigned to ivabradine or digoxin according to a randomization cross-over design. Data were single-blind analyzed. The analysis was performed using an intention-to-treat method. Forty-two coronary patients were selected. In spite of maximally tolerated therapy with renin-antagonists, diuretics and β-blockers, they had congestive diastolic heart failure with preserved systolic function. Both ivabradine and digoxin had positive effects on dyspnea, Nterminal natriuretic peptide, heart rate, duration of 6-min. walk-test and signs of diastolic dysfunction, but digoxin was high-statistically more effective. Side-effects were irrelevant. Data were obtained in a single-center and from 42 patients with ischemic etiology of heart failure. The number of patients is small and does not allow assessing mortality. In coronary patients with symptomatic diastolic heart failure with preserved systolic function low-dose digoxin was significantly more effective than ivabradine and is much cheaper. One should be more critical about ivabradine and low-dose digoxin in diastolic heart failure. To avoid possible negative effects on the cardiac function and a severe reduction of the cardiac output the resting heart rate should not be decreased to <65 beats/min.

Standard nonspecific therapies in the management of pulmonary arterial hypertension

Recent advances in pulmonary arterial hypertension (PAH) research have created a new era of PAH-specific therapies. Although these therapeutics have revolutionized PAH therapy, their innovation was predated by supportive but nonspecific medical therapies adapted from their use in more common cardiopulmonary diseases. These therapies include oxygen therapy, diuretics, digoxin, anticoagulation, and high-dose calcium channel blockers. Expert opinion continues to support the use of adjunct therapies based on current pathologic understandings of PAH combined with some evidence extrapolated from small studies. This article discusses why these therapies continue to play an important role in the treatment of patients with PAH.