Digitalis Investigation Group

Objectives:

To determine the effect of increasing age on mortality, hospitalizations, and digoxin side effects in patients with heart failure (HF), and to determine whether the effect of digoxin on clinical outcomes varies as a function of age.

Background:

The incidence and prevalence of HF increase with advancing age, but there are limited data on the clinical course and response to specific interventions in elderly patients with HF.

Subjects:

A total of 302 centers in the United States and Canada enrolled 7,788 patients between February 1991 and September 1993.

Design:

The Digitalis Investigation Group (DIG) study was a prospective, randomized clinical trial involving 7,788 patients with HF randomized to digoxin or placebo and followed for an average of 37 months. Interactions between age and the following clinical outcomes were examined: total mortality, all-cause hospitalizations, HF hospitalizations, the composite of HF death or HF hospitalizations, hospitalization for suspected digoxin toxicity and withdrawal from therapy because of side effects.

Conclusions:

Increasing age is associated with progressively worse clinical outcomes in patients with HF. However, the beneficial effects of digoxin in reducing all-cause admissions, HF admissions, and HF death or hospitalization are independent of age. Thus, digoxin remains a useful agent to the adjunctive treatment of HF due to impaired left ventricular systolic function in patients of all ages.