Digoxin Investigation Group - DIG

Description:

Digoxin for mortality in congestive heart failure.

Hypothesis:

Digitalis therapy, when added to treatment with angiotensin-converting enzyme (ACE) inhibitors and diuretics, improves survival in patients with congestive heart failure.

Study Design

  • Placebo Controlled
  • Randomized
  • Parallel

Patients Screened: Not available
Patients Enrolled: 7,788 (6,800 patients were randomized)
NYHA Class: I=(14%), II=(54%), III=(30%), IV=(2%)
Mean Follow Up: 37 months (28-58 months)
Mean Patient Age: 72
Female: 25%
Mean Ejection Fraction: 29%

Patient Populations:

  • History of clinical heart failure with current or prior evidence of low output (limitation of activity)
  • Normal sinus rhythm
  • Chest x-ray and ejection fraction within 6 months
  • Evidence of congestion (edema, jugular venous distention, rales, chest x-ray)

Exclusions:

  • Age <21 years
  • No available ejection fraction
  • Atrial fibrillation or flutter
  • Restrictive or hypertrophic cardiomyopathy
  • 2-degree or 3-degree heart block
  • Wolff-Parkinson-White syndrome
  • Recent myocardial infarction or cardiac surgery
  • Unstable angina
  • Hyper- or hypokalemia
  • Current parenteral inotropes
  • Significant comorbidity

Primary Endpoints:

  • Total mortality in heart failure patients with left ventricular ejection fraction <0.45

Secondary Endpoints:

  • Reduction in hospitalization for worsening congestive heart failure
  • Cardiovascular mortality
  • Death due to progressive heart failure
  • All-cause hospitalization
  • Quality of life
  • Ancillary study (approximately 1,000 patients) assessed death and hospitalizations for congestive heart failure in a group of patients with an ejection fraction >0.45 (parallel but separate study)

Drug/Procedures Used:

Digoxin dose (based on algorithm) range, 0.125 to 0.5 mg/day

Concomitant Medications:

ACE inhibitors (93%), diuretics (82%), and nitrates (42%)

Principal Findings:

Overall, 6,800 patients were randomized. The mean age was 72 years, 25% were women, 29% had diabetes, 62% had chronic kidney disease, mean body mass index was 26 kg/m2, mean systolic blood pressure was 128 mm Hg, mean left ventricular ejection fraction was 29%, and 68% had a prior myocardial infarction. 72% of participants received digoxin 0.25 mg daily and 25% received digoxin 0.125 mg daily.

Digoxin had a neutral effect on mortality.

Digoxin reduced hospitalization and favorably affected the combined endpoint of death or hospitalization due to worsening congestive heart failure.

Among a cohort of patients ≥65 years, hospital admission at 30 days occurred in 5.4% of the digoxin group vs. 8.1% of the placebo group (p = 0.002). This was primarily due to a reduction in heart failure hospitalizations. This beneficial effect was observed at 60 days (hazard ratio 0.76, p = 0.003) and 90 days (hazard ratio 0.75, p < 0.001).

There was a trend toward increased death due to arrhythmic events in certain groups.

There was a low incidence of digoxin toxicity.

Interpretation:

Digoxin was shown to be safe, and clinical morbidity benefits are incremental to ACE inhibitor and diuretic therapy. Among a cohort of older patients, digoxin reduced hospital admission primarily due to a reduction in heart failure admissions. This medication may need to be restudied in a contemporary setting.

References:

Bourge RC, Fleg JL, Fonarow GC, et al. Digoxin reduces 30-day all-cause hospital admission in older patients with chronic systolic heart failure. Am J Med 2013;Mar 11:[Epub ahead of print].

Presented by Dr. Ali Ahmed at ACC.13, San Francisco, March 11, 2013.

1. Control Clin Trials 1996;17:77-97. Design and baseline results.
2. N Engl J Med 1997;336:525-33. Final results.

Clinical Topics: Heart Failure and Cardiomyopathies, Acute Heart Failure

Keywords: Myocardial Infarction, X-Rays, Digoxin, Diuretics, Digitalis Glycosides, Edema, Systole, Body Mass Index, Heart Failure, Stroke Volume, Respiratory Sounds, Diabetes Mellitus, Renal Insufficiency, Chronic


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