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Aims: Many patients with heart failure and reduced EF remain at high risk for hospitalization despite evidence-based therapy. Digoxin may decrease hospitalization; however, uncertainty persists concerning its proper administration and effect on mortality. This study investigated whether using dose response concepts to re-evaluate the relationship between serum digoxin concentration and key mortality outcomes in patients with reduced EF in the Digitalis Investigation Group trial would help clarify efficacy and safety., Methods and Results: Multivariable Cox proportional hazards modelling and propensity score adjustment assessed the relationship between serum digoxin concentration (≥0.5 ng/mL) as a continuous variable and mortality outcomes. In patients treated with digoxin, a significant linear association was found between serum concentration and all-cause mortality [adjusted hazard ratio (HR) 1.25, 95% confidence interval (CI) 1.14-1.38, P < 0.001 per 0.5 ng/mL increase in serum concentration]. Based on this relationship, a bidirectional association was found between digoxin therapy and all-cause mortality when compared with placebo. The lowest serum concentrations (0.5-0.7 ng/mL) were associated with the lowest risk of all-cause mortality (adjusted HR 0.77, 95% CI 0.67-0.89, P < 0.001) while high serum concentrations (1.6-2.0 ng/mL) were associated with increased mortality (adjusted HR 1.33, 95% CI 1.12-1.58, P = 0.001). Consistent with this finding, lower serum concentrations (0.5-0.7 ng/mL) were associated with reduced death from worsening heart failure and a neutral effect on cardiovascular death not due to worsening heart failure., Conclusion: These findings favour targeting serum concentrations from 0.5 to 0.7 ng/mL when dosing digoxin in patients with heart failure and reduced EF., (© 2016 The Authors. European Journal of Heart Failure © 2016 European Society of Cardiology.)

Digoxin improves exercise tolerance and reduces hospitalizations in patients with systolic heart failure, but its use has declined progressively for the past two decades. The Digitalis Investigation Group trial showed that digoxin reduced hospitalizations but had a neutral effect on total mortality. There was evidence that mortality caused by worsening heart failure was less, but there was also a signal suggesting an increase in other cardiac (presumed arrhythmic) death. Use of digoxin has declined substantially and recent guideline recommendations have significantly de-emphasized the importance of this drug in the management of heart failure. Two developments suggest that re-evaluation of the contemporary role of digoxin in the management of heart failure with reduced ejection fraction is warranted. First, heart failure remains progressive, characterized by chronic debility, exercise intolerance, and frequent and costly hospitalizations, despite evidence-based drug and device therapies that prolong survival. Health economics have made reducing hospitalizations in patients with heart failure a major priority. Second, a strong association has emerged between serum concentration and the safety and efficacy of digoxin, which indicates a change in our approach to dosing this agent is needed. Experimental and clinical results suggest that optimizing therapeutic benefit and avoiding harm means dosing to achieve low serum digoxin concentrations (0.5-0.9 ng/mL). Digoxin is an inexpensive agent and the totality of evidence indicates that it reduces hospitalizations and improves symptoms safely when dosed to achieve low serum concentrations. These findings suggest digoxin should have a more prominent therapeutic role in patients with heart failure and reduced ejection fraction., (© 2014 The Authors. European Journal of Heart Failure © 2014 European Society of Cardiology.)

Aims: In the Digitalis Investigation Group (DIG) trial, digoxin reduced mortality or hospitalization due to heart failure (HF) in several pre-specified high-risk subgroups of HF patients, but data on protocol-specified 2-year outcomes were not presented. In the current study, we examined the effect of digoxin on HF death or HF hospitalization and all-cause death or all-cause hospitalization in high-risk subgroups during the protocol-specified 2 years of post-randomization follow-up., Methods and Results: In the DIG trial, 6800 ambulatory patients with chronic HF, normal sinus rhythm, and LVEF ≤45% (mean age 64 years, 26% women, 17% non-whites) were randomized to receive digoxin or placebo. The three high-risk groups were defined as NYHA class III-IV symptoms (n = 2223), LVEF <25% (n = 2256), and cardiothoracic ratio (CTR) >55% (n = 2345). In all three high-risk subgroups, compared with patients in the placebo group, those in the digoxin group had a significant reduction in the risk of the 2-year composite endpoint of HF mortality or HF hospitalization: NYHA III-IV [hazard ratio (HR) 0.65; 95% confidence interval (CI) 0.57-0.75; P < 0.001], LVEF <25% (HR 0.61; 95% CI 0.53-0.71; P < 0.001), and CTR >55% (HR 0.65; 95% CI 0.57-0.75; P < 0.001). Digoxin-associated HRs (95% CI) for 2-year all-cause mortality or all-cause hospitalization for subgroups with NYHA III-IV, LVEF <25%, and CTR >55% were 0.88 (0.80-0.97; P = 0.012), 0.84 (0.76-0.93; P = 0.001), and 0.85 (0.77-0.94; P = 0.002), respectively., Conclusions: Digoxin improves outcomes in chronic HF patients with NYHA class III-IV, LVEF <25%, or CTR >55%, and should be considered in these patients.

Background: About half of the 5 million heart failure patients in the United States have diastolic heart failure (clinical heart failure with normal or near-normal ejection fraction). Except for candesartan, no drugs have been tested in randomized clinical trials in these patients. Although digoxin was tested in an appreciable number of diastolic heart failure patients in the Digitalis Investigation Group ancillary trial, detailed findings from this important study have not previously been published., Methods and Results: Ambulatory chronic heart failure patients (n = 988) with normal sinus rhythm and ejection fraction > 45% (median, 53%) from the United States and Canada (1991 to 1993) were randomly assigned to digoxin (n = 492) or placebo (n = 496). During follow-up with a mean length of 37 months, 102 patients (21%) in the digoxin group and 119 patients (24%) in the placebo group (hazard ratio [HR], 0.82; 95% confidence interval [CI], 0.63 to 1.07; P = 0.136) experienced the primary combined outcome of heart failure hospitalization or heart failure mortality. Digoxin had no effect on all-cause or cause-specific mortality or on all-cause or cardiovascular hospitalization. Use of digoxin was associated with a trend toward a reduction in hospitalizations resulting from worsening heart failure (HR, 0.79; 95% CI, 0.59 to 1.04; P = 0.094) but also a trend toward an increase in hospitalizations for unstable angina (HR, 1.37; 95% CI, 0.99 to 1.91; P = 0.061)., Conclusions: In ambulatory patients with chronic mild to moderate diastolic heart failure and normal sinus rhythm receiving angiotensin-converting enzyme inhibitor and diuretics, digoxin had no effect on natural history end points such as mortality and all-cause or cardiovascular hospitalizations.

Aims: To determine the effects of digoxin on all-cause mortality and heart failure (HF) hospitalizations, regardless of ejection fraction, accounting for serum digoxin concentration (SDC)., Methods and Results: This comprehensive post-hoc analysis of the randomized controlled Digitalis Investigation Group trial (n=7788) focuses on 5548 patients: 1687 with SDC, drawn randomly at 1 month, and 3861 placebo patients, alive at 1 month. Overall, 33% died and 31% had HF hospitalizations during a 40-month median follow-up. Compared with placebo, SDC 0.5-0.9 ng/mL was associated with lower mortality [29 vs. 33% placebo; adjusted hazard ratio (AHR), 0.77; 95% confidence interval (CI), 0.67-0.89], all-cause hospitalizations (64 vs. 67% placebo; AHR, 0.85; 95% CI, 0.78-0.92) and HF hospitalizations (23 vs. 33% placebo; AHR, 0.62; 95% CI, 0.54-0.72). SDC> or =1.0 ng/mL was associated with lower HF hospitalizations (29 vs. 33% placebo; AHR, 0.68; 95% CI, 0.59-0.79), without any effect on mortality. SDC 0.5-0.9 reduced mortality in a wide spectrum of HF patients and had no interaction with ejection fraction >45% (P=0.834) or sex (P=0.917)., Conclusions: Digoxin at SDC 0.5-0.9 ng/mL reduces mortality and hospitalizations in all HF patients, including those with preserved systolic function. At higher SDC, digoxin reduces HF hospitalization but has no effect on mortality or all-cause hospitalizations.

Objectives: The purpose of this study was to investigate the relationship of serum digoxin concentration (SDC) and outcomes in women with heart failure (HF)., Background: Controversy continues concerning the clinical utility of digoxin in women with HF., Methods: Our analysis was retrospective with data from the Digitalis Investigation Group (DIG) trial. The principal study analysis reviewed 4,944 patients with HF due to systolic dysfunction who survived for at least 4 weeks (all 3,366 patients randomized to placebo and the 1,578 of 3,372 patients randomized to digoxin who had serum concentration measured 6 to 30 h [inclusive] after the last dose of study drug at 4 weeks)., Results: Continuous multivariable analysis demonstrated a significant linear relationship between SDC and mortality in women (p = 0.008) and men (p = 0.002, p = 0.766 for gender interaction). Averaging hazard ratios (HRs) across serum concentrations from 0.5 to 0.9 ng/ml in women produced a HR for death of 0.8 (95% confidence interval [CI] 0.62 to 1.13, p = 0.245) and for death or hospital stay for worsening HF of 0.73 (95% CI 0.58 to 0.93, p = 0.011). In contrast, SDCs from 1.2 to 2.0 ng/ml were associated with a HR for death for women of 1.33 (95% CI 1.001 to 1.76, p = 0.049)., Conclusions: Retrospective analysis of data from the DIG trial indicates a beneficial effect of digoxin on morbidity and no excess mortality in women at serum concentrations from 0.5 to 0.9 ng/ml, whereas serum concentrations > or =1.2 ng/ml seem harmful.

Objectives: We sought to determine whether there was a relationship between serum digoxin concentration (SDC), including SDCs typically regarded as low, and clinical efficacy related to digoxin in patients with symptomatic left ventricular dysfunction., Background: Digitalis glycosides have been used for 200 years in the treatment of heart failure (HF), but the SDC required for optimal clinical efficacy and acceptable toxicity remains controversial., Methods: This relationship was investigated by utilizing data from two randomized, double-blinded, placebo-controlled, digoxin-withdrawal trials: the Prospective Randomized study Of Ventricular failure and Efficacy of Digoxin (PROVED) and the Randomized Assessment of Digoxin on Inhibitors of Angiotensin-Converting Enzyme (RADIANCE). Major end points were worsening HF, change in left ventricular ejection fraction and treadmill time after randomization. The primary analysis investigated the relationship between SDC at randomization and these end points. A secondary categorical analysis compared these end points in patients who discontinued digoxin versus patients who continued digoxin and had low (0.5 to 0.9 ng/ml), moderate (0.9 to 1.2 ng/ml) or high (>1.2 ng/ml) SDCs at randomization., Results: Multiple regression analysis failed to find a relationship between randomization SDC, considered as a continuous variable, and any study end point (all p > 0.236). Multivariable Cox analysis found that the risk of worsening HF was significantly less (all p < 0.02) for patients in any category of SDC who continued digoxin, as compared with patients withdrawn from digoxin. Specifically, patients in the low SDC category were significantly less likely than placebo patients to experience worsening HF during follow-up (p = 0.018)., Conclusions: The beneficial effects of digoxin on common clinical end points in patients with HF were similar, regardless of SDC.

Byline: Kirkwood F. Adams, Mihai Gheorghiade, Barry F. Uretsky, James B. Young, J.Herbert Patterson, Lisa Tomasko, Milton Packer Abstract: Previous work provides limited information concerning predictors of clinical deterioration after digoxin withdrawal. We investigated the association between selected baseline clinical characteristics and symptomatic deterioration in two similarly designed trials: Prospective Randomized Study of Ventricular Function and Efficacy of Digoxin (PROVED) and Randomized Assessment of Digoxin and Inhibitors of Angiotensin-Converting Enzyme (RADIANCE). Cox proportional-hazards analysis found the following independent predictors of worsening during follow-up in the combined PROVED and RADIANCE patients: heart failure score, left ventricular ejection fraction, cardiothoracic ratio, use of an angiotensin-converting enzyme inhibitor, use of digoxin, and age. When these factors, except for digoxin use, were tested in the subgroup of patients withdrawn from digoxin, they all were significant independent predictors of worsening heart failure. In contrast, only use of angiotensin-converting enzyme inhibitor predicted deterioration in patients who continued digoxin. Patients with more congestive symptoms, worse ventricular function, greater cardiac enlargement, or who were not taking an angiotensin-converting enzyme inhibitor were significantly more likely to worsen early after digoxin discontinuation than patients without these characteristics.(Am Heart J 1998;135:389-97.) Author Affiliation: Chapel Hill, N.C.; Chicago, Ill.; Galveston, Texas; Cleveland, Ohio; and New York, N.Y Article History: Received 26 September 1996; Accepted 12 August 1997 Article Note: (footnote) [star] From the aDepartments of Medicine and Radiology, School of Medicine, the bSchool of Pharmacy, and the cDepartment of Biostatistics, School of Public Health, University of North Carolina at Chapel Hill; dDepartment of Medicine, Northwestern University Medical School; eDepartment of Medicine, University of Texas Medical Branch; fDepartment of Cardiology, Cleveland Clinic Foundation; and the gCenter for Heart Failure Research, Columbia University College of Physicians and Surgeons., [star][star] Supported in part by PHS Research MO1 RR00046 from the General Clinical Research Centers branch of the Division of Research Resources., a Reprint requests: Kirkwood F. Adams, Jr., MD, Division of Cardiology, University of North Carolina at Chapel Hill, CB# 7075, Burnett-Womack Building, Chapel Hill, NC 27599-7075. E-mail:kfa@med.unc.edu, aa 0002-8703/98/$5.00 + 0 4/1/86039

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. [ABSTRACT FROM AUTHOR]

Background: Although digoxin is effective in the treatment of patients with chronic heart failure who are receiving diuretic agents, it is not clear whether the drug has a role when patients are receiving angiotensin-converting-enzyme inhibitors, as is often the case in current practice. Methods: We studied 178 patients with New York Heart Association class II or III heart failure and left ventricular ejection fractions of 35 percent or less in normal sinus rhythm who were clinically stable while receiving digoxin, diuretics, and an angiotensin-converting-enzyme inhibitor (captopril or enalapril). The patients were randomly assigned in a double-blind fashion either to continue receiving digoxin (85 patients) or to be switched to placebo (93 patients) for 12 weeks. Otherwise, their medical therapy for heart failure was not changed. Results: Worsening heart failure necessitating withdrawal from the study developed in 23 patients switched to placebo, but in only 4 patients who continued to receive digoxin (P<0.001). The relative risk of worsening heart failure in the placebo group as compared with the digoxin group was 5.9 (95 percent confidence interval, 2.1 to 17.2). All measures of functional capacity deteriorated in the patients receiving placebo as compared with those continuing to receive digoxin (P = 0.033 for maximal exercise tolerance, P = 0.01 for submaximal exercise endurance, and P = 0.019 for New York Heart Association class). In addition, the patients switched from digoxin to placebo had lower quality-of-life scores (P = 0.04), decreased ejection fractions (P = 0.001), and increases in heart rate (P = 0.001) and body weight (P<0.001). Conclusions: These findings indicate that the withdrawal of digoxin carries considerable risks for patients with chronic heart failure and impaired systolic function who have remained clinically stable while receiving digoxin and angiotensin-converting-enzyme inhibitors. (N Engl J Med 1993;329:1-7.) [ABSTRACT FROM AUTHOR]