Digoxin in advanced heart failure patients: a question of rhythm

Digoxin is Not Related to Mortality in Patients with Heart Failure: Results from the SELFIE-TR Registry

AIMS

Digoxin has been used in the treatment for heart failure for centuries, but the role of this drug in the modern era is controversial. A particular concern is the recent observational findings suggesting an increase in all-cause mortality with digoxin, although such observations suffer from biased results since these studies usually do not provide adequate compensation for the severity of disease. Using a nationwide registry database, we aimed to investigate whether digoxin is associated with 1-year all-cause mortality in patients with heart failure irrespective of phenotype.

METHODS

A total of 1014 out of 1054 patients in the registry, of whom 110 patients were on digoxin, were included in the study. Multivariable adjustments were done and propensity scores were calculated for various prognostic indicators, including signs and symptoms of heart failure and functional capacity. Crude mortality, mortality adjusted for covariates, mortality in the propensity score-matched cohort, and Bayesian factors (BFs) were analyzed.

RESULTS

Crude 1-year mortality rate did not differ between patients on and off digoxin (17.3% vs 20.1%, log-rank p = 0.46), and digoxin was not related to mortality following multivariable adjustment (hazard ratio 0.87, 95% confidence interval 0.539-1.402, p = 0.57). Similarly, all-cause mortality was similar in 220 propensity-score adjusted patients (17.3% vs 20.0%, log-rank p = 0.55). On Bayesian analyses, there was moderate to strong evidence suggesting a lack of difference between in unmatched cohort (BF10 0.091) and weak-to-moderate evidence in the matched cohort (BF10 0.296).

CONCLUSIONS

In this nationwide cohort, we did not find any evidence for an increased 1-year mortality in heart failure patients on digoxin.

Factors associated with unjustified chronic treatment with digoxin in patients with acute heart failure and relationship with short-term prognosis

OBJECTIVES

To analyze the factors related to inadequate chronic treatment with digoxin and whether the inadequacy of treatment has an impact on short-term outcome.

METHOD

Patients diagnosed with AHF who were in chronic treatment with digoxin, were selected. Digoxin treatment was classified as adequate or inadequate. We investigated factors associated to inadequacy and whether such inadequacy was associated with in-hospital and 30-day mortality, prolonged hospital stay (>7 days) and combined adverse event (re-consultation to the ED or hospitalization for AHF or death from any cause) during the 30 days after discharge.

RESULTS

We analyzed 2,366 patients on chronic digoxin treatment (median age = 83 years, women = 61%), which was considered adequate in 1,373 cases (58.0%) and inadequate in 993 (42.0%). The inadequacy was associated with older age, less comorbidity, less treatment with beta-blockers and renin-angiotensin inhibitors, better ventricular function, and worse Barthel index. In-hospital and 30-day mortality was higher in patients with inadequate digoxin treatment (9.9% versus 7.6%, p = 0.05; and 12.6% versus 9.1%, p < 0.001, respectively). No differences were recorded in prolonged stay (35.7% versus 33.8%) or post-discharge adverse events (32.9% versus 31.8%). In the model adjusted for baseline and decompensation episode differences, inadequate treatment with digoxin was not significantly associated with any outcome, with an odds ratio of 1.31 (95%CI = 0.85-2.03) for in-hospital mortality; 1.29 (0.74-2.25) for 30-day mortality; 1.07 (0.82-1.40) for prolonged stay; and 0.88 (0.65-1.19) for post-discharge adverse event.

CONCLUSION

There is a profile of patients with AHF who inadequately receive digoxin, although this inadequateness for chronic digitalis treatment was not associated with short-term adverse outcomes.

Digoxin in patients with advanced heart failure and sinus rhythm submitted to cardiac resynchronization therapy- is there any benefit?

ABSTRACT

Digoxin use in patients with heart failure with reduced ejection fraction (HFrEF) and sinus rhythm remains controversial. We aimed to assess the prognostic impact of digoxin in patients in sinus rhythm submitted to cardiac resynchronization therapy (CRT).Retrospective study including 297 consecutive patients in sinus rhythm, with advanced HFrEF submitted to CRT. Patients were divided into two groups - with digoxin (DG) and without digoxin (NDG). During a mean follow-up of 4.9 ± 3.4 years we evaluated the impact of digoxin on the composite endpoint defined as cardiovascular hospitalization, progression to heart transplantation and all-cause mortality.Previous to CRT, 104 patients (35%) were chronically under digoxin and 193 patients (65%) without digoxin treatment. The 2 groups did not differ significantly regarding HF functional class, HF aetiology, QRS and baseline left ventricular ejection fraction (LVEF). The proportion of responders to CRT was similar in both groups (54% in DG vs 56% in NDG, p=0.78). During the long term follow up period, the primary endpoint occurred in a higher proportion in DG patients (67 vs 48%, p=0.002). After adjustment for potential confounders, digoxin use remained as an independent predictor of the composite endpoint of CV hospitalization, heart transplantation and all-cause mortality (HR = 1.58, CI 95 [1.01 - 2.46], p = 0.045).In conclusion, in patients in sinus rhythm with HFrEF submitted to CRT, digoxin use was associated to CV hospitalization, progression to heart transplant and all-cause mortality.

Is foxglove effective in heart failure?

BACKGROUND

Digoxin is the oldest known treatment for heart failure (HF) and has been demonstrated to reduce admissions for worsening heart failure in a large randomized trial recruiting patients in sinus rhythm with heart failure and ejection fraction <45%. This study forms the basis for current international guidelines recommending that digoxin should be considered in patients with symptomatic HF despite optimal doses of angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, β-blockers, and mineralocorticoid receptor antagonists in addition to device therapy, if indicated. However, digoxin predates mortality reducing HF therapies, and this article reviews the historical and recent data.

METHODS

Multiple PubMed searches were performed including, but not limited to, the search terms "digoxin," "heart failure," "efficacy," "treatment," "side-effects," "morbidity," "mortality," and "arrythmia." Articles were excluded if not relevant, not in English or without abstract. Reference lists of relevant articles were manually searched for further references. Due to the large number of articles retrieved, a selection was reviewed based on the authors' best judgement.

RESULTS

Three randomized controlled trials and three large contemporary observational reports of digoxin therapy in heart failure and sinus rhythm were retrieved. Other studies were noted that included patients with heart failure and atrial fibrillation, which were also reviewed.

CONCLUSION

Definitive randomized evidence of digoxin efficacy as add-on therapy in HF is lacking because most landmark trials of modern HF disease modifying agents postdate the randomized studies of digoxin. Furthermore, questions remain regarding the optimum dose of digoxin and there are signals that digoxin may be harmful in some patients with HF. All contemporary data for digoxin in HF are derived from observational studies and the findings are conflicting. Despite two centuries of experience using cardiac glycosides to treat HF, fundamental questions regarding the efficacy and safety of digoxin in HF remain unanswered.

Should β-blockers be used in patients with heart failure and atrial fibrillation?

PURPOSE

There is overwhelming evidence that β-blockers reduce cardiovascular hospitalizations and mortality in patients with heart failure and a reduced left ventricular ejection fraction provide they are in sinus rhythm. However, a recent meta-analysis of individual patient data provides compelling evidence that β-blockers are not effective in patients with heart failure and atrial fibrillation, although neither did they increase risk. The purpose of this article is to review the evidence, seek possible explanations for this observation, and make recommendations based on the limited evidence available.

METHODS

Review and critical analysis of recent publications and meta-analyses on the use of β-blockers and other heart rate-slowing medicines in heart failure.

FINDINGS

The reasons for the lack of effect of β-blockers in patients with heart failure are uncertain. There is a substantial body of evidence to suggest that patients with heart failure and atrial fibrillation who have less stringent ventricular rate control have a better outcome. The most plausible explanation for these findings, in our view, is that β-blockers exert similar benefits through similar mechanisms regardless of intrinsic heart rhythm but that the benefits of β-blockers are neutralized in patients with atrial fibrillation due to the induction of pauses that may impair cardiac function leading to worsening heart failure or cause arrhythmias resulting in death.

IMPLICATIONS

Smaller doses of β-blockers and other rate lowering agents to achieve a resting clinic heart rate in the range of 75-89beats/min might improve outcome. Preventing pauses by pacing or pulmonary vein ablation of atrial fibrillation are strategies that should be researched.

Safety and efficacy of digoxin: systematic review and meta-analysis of observational and controlled trial data

OBJECTIVE

To clarify the impact of digoxin on death and clinical outcomes across all observational and randomised controlled trials, accounting for study designs and methods.

DATA SOURCES AND STUDY SELECTION

Comprehensive literature search of Medline, Embase, the Cochrane Library, reference lists, and ongoing studies according to a prospectively registered design (

PROSPERO

CRD42014010783), including all studies published from 1960 to July 2014 that examined treatment with digoxin compared with control (placebo or no treatment).

DATA EXTRACTION AND SYNTHESIS

Unadjusted and adjusted data pooled according to study design, analysis method, and risk of bias.

MAIN OUTCOME MEASURES

Primary outcome (all cause mortality) and secondary outcomes (including admission to hospital) were meta-analysed with random effects modelling.

RESULTS

52 studies were systematically reviewed, comprising 621,845 patients. Digoxin users were 2.4 years older than control (weighted difference 95% confidence interval 1.3 to 3.6), with lower ejection fraction (33% v 42%), more diabetes, and greater use of diuretics and anti-arrhythmic drugs. Meta-analysis included 75 study analyses, with a combined total of 4,006,210 patient years of follow-up. Compared with control, the pooled risk ratio for death with digoxin was 1.76 in unadjusted analyses (1.57 to 1.97), 1.61 in adjusted analyses (1.31 to 1.97), 1.18 in propensity matched studies (1.09 to 1.26), and 0.99 in randomised controlled trials (0.93 to 1.05). Meta-regression confirmed that baseline differences between treatment groups had a significant impact on mortality associated with digoxin, including markers of heart failure severity such as use of diuretics (P=0.004). Studies with better methods and lower risk of bias were more likely to report a neutral association of digoxin with mortality (P<0.001). Across all study types, digoxin led to a small but significant reduction in all cause hospital admission (risk ratio 0.92, 0.89 to 0.95; P<0.001; n=29,525).

CONCLUSIONS

Digoxin is associated with a neutral effect on mortality in randomised trials and a lower rate of admissions to hospital across all study types. Regardless of statistical analysis, prescription biases limit the value of observational data.