Serum digoxin levels and mortality in 5,100 patients.

A retrospective study of 5,100 patients on digoxin, with a four-week follow up after digoxin levels were measured, was done to determine the mortality rate. A significant increase in mortality was correlated with an increasing serum digoxin level, up to 50% at a level of 6.0 ng/mL and more. Clinical toxicity was suspected in only 0.25% of all patients on digoxin, although almost 10% had levels above the therapeutic range. Deliberate digoxin overdoses were fatal in 50% of cases. This study shows a correlation between increasing digoxin levels and increasing mortality rates. We recommend the use of serum digoxin measurements to identify those asymptomatic patients with elevated levels. The physician should seriously consider the indications for initiating or continuing digoxin treatment in any patient because of an increased mortality in patients with levels of more than 1.0 ng/mL.