Digoxin, a drug derived from the foxglove plant, is one of the oldest and most widely used treatments for a variety of cardiac conditions. For example, it can regularize the heartbeat in many who have atrial fibrillation and it can strengthen the heart beat for those with heart failure. A new study published in the journal Circulation, however, suggests that its use for adults with heart failure (HF) should be reevaluated.
Dr. James V. Freeman and associates from the Kaiser Permanente Northern California health care system identified almost 3,000 adults who were newly diagnosed with heart failure between 2006 and 2008, who had not previously used digoxin. The investigators examined the patients records to see if there was an association between digoxin use and both risk of death and risk of hospitalization for HF. (HF is very common among older Americans, is manifested by inadequate blood flow due to weakened heart muscle from high blood pressure or heart attack, and causes weakness, leg swelling and shortness of breath).
In their analyses, the researchers controlled for a variety of factors that might affect their results, such as medical history, other medications, and the severity of HF. Among the 2891 patients they identified with newly diagnosed HF, 18 percent were prescribed digoxin. The patients were followed for a median of 2.5 years. During that time, they found a 72 percent increased risk of death in those who used digoxin, but no increased likelihood of hospitalization for HF.
Since this study is retrospective and non-randomized, one cannot impute causation. However, if these results are confirmed by other investigators, it may well mean that the widespread use of digoxin for treating HF might have to be reassessed.
ACSH s Dr. Gilbert Ross had this perspective: Digoxin has been widely used for decades, and this study, while far from dispositive, is certainly of great concern. There is little question of digoxin (the most commonly used but not the only cardiac glycoside) being key to rate control in patients with rapid atrial fibrillation. But for the treatment of HF in patients with normal rate and rhythm, we now have at least the grounds for discussion. It s difficult to ignore such a major increase in death rate. My question: how well were confounders controlled for? Is it not possible that the sicker patients were more likely to be prescribed digoxin, thus accounting for their higher mortality?