Digitalis May Increase Mortality in Patients With Atrial Fibrillation

NEW YORK (Reuters Health) Feb 22 - Patients with atrial fibrillation who are treated with digitalis may be at increased risk of death, according to findings from an observational study by Scandinavian and US researchers.

In the February issue of Heart, Dr. Knut Gjesdal of the University of Oslo, Norway and colleagues note that digitalis increases exercise capacity and reduces morbidity in patients with heart failure.

They point out, however, that there is no survival benefit, which "raises the suspicion that the inotropic benefits of digitalis may be counteracted by serious adverse effects."

To investigate this theory, the researchers examined data from a study involving 7,329 moderate to high risk patients with atrial fibrillation. At baseline, 53.4% were receiving digitalis therapy. These patients had a mortality rate of 6.5%, versus 4.1% in nonusers (hazard ratio, 1.58).

The difference in mortality persisted after adjustment for age, body mass index, diabetes and hypertension (hazard ratio, 1.53).

Dr. Gjesdal told Reuters Health, "We think the report should be regarded as a whistle blow: there may be a mortality problem with digitalis."

"The only method for settling the matter," he continued, "would be to perform a randomized controlled clinical trial on digitalis versus placebo in atrial fibrillation, with mortality as the primary outcome. For obvious reasons such a trial could hardly be done."

Still, the researchers call for further studies. They conclude, "If digitalis does have serious adverse effects, the number of patients affected might be large."