Meta-analysis confirms patients treated with digoxin are at increased risk of death

Increased mortality is as high as 21% in patients with congestive heart disorder, a study reveals.

Patients taking the heart failure drug digoxin have a heightened risk of death, according to the largest meta-analysis of its kind. Digoxin is extracted from the digitalis lanata plant (pictured), commonly known as woolly foxglove

Patients taking the heart failure drug digoxin have a heightened risk of death, according to the largest meta-analysis of its kind. This has led researchers to urge “great caution” and close monitoring when prescribing the drug, particularly for heart-rate control in atrial fibrillation (AF) patients.

A total of 19 studies, based on 326,426 patients, were analysed and published in the European Heart Journal
[1]
, revealing a 21% increase in mortality for patients with congestive heart failure (CHF) or AF receiving the glycoside compared with patients not receiving digoxin (hazard ratio 1.21, 95% confidence interval [CI] 1.07–1.38; P<0.01).

This increased risk was especially pronounced, at 29%, in the subset of patients with AF (n=235,047) who received digoxin compared with those who did not receive the drug (HR 1.29, 95% CI 1.07–1.38). Among patients with congestive heart failure, those who received digoxin had a 14% increase in mortality (HR 1.14, 95% CI 1.06–1.22).

Maureen Talbot, senior cardiac nurse at the British Heart Foundation, who was not involved in the study, says: “This large analysis shows clearly for the first time that patients taking digoxin have an increased risk of dying.”

Digoxin has been prescribed for many years, says Talbot, and the need for careful monitoring has been long recognised. The drug has a narrow therapeutic range and maintaining strict serum levels is essential.

There is only one randomised controlled trial that has examined the use of digoxin for treatment of chronic heart failure. It showed no effect on mortality but a slight reduction in the likelihood of hospital admission.

A post-hoc analysis of the data revealed that higher serum levels of digoxin were associated with an increased risk of dying but that lower concentrations seemed to have clinical benefit. There are no randomised controlled trials to support digoxin’s use in rate control for AF. Retrospective and observational studies have found digoxin to be associated with an increased risk of death, which has raised serious concerns about its safety.

“There is conflicting evidence about digoxin’s benefit, which is why the number of prescriptions for it has been steadily decreasing for years,” says Talbot. Nonetheless, the medicine is endorsed in clinical guidelines produced by both the European Society of Cardiology and the American Heart Association.

The study authors, Mate Vamos, Julia Erath and Stefan Hohnloser, from the Department of Cardiology at Goethe University, call for randomised trials of dose-adjusted digoxin therapy, at least in CHF.

“Until such proper randomised controlled trials are being completed, digoxin should be used with great caution (including monitoring plasma levels), particularly when administered for rate control in AF,” they recommend.

The British Heart Foundation does not recommend patients being treated with digoxin stop taking their medication, but suggests they consult their GP if concerned.

References

[1] Vamos M, Erath JW & Hohnloser SH. Digoxin-associated mortality: a systematic review and meta-analysis of this literature. European Heart Journal 2015. doi:10.1093/eurheart/ehv143.

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Citation
The Pharmaceutical Journal, PJ, 23/30 May 2015, Vol 294, No 7863/4;294(7863/4):DOI:10.1211/PJ.2015.20068510