What is the economic value of digoxin therapy in congestive heart failure patients? Results from the DIG trial.

BACKGROUND: The Digitalis Investigation Group (DIG) clinical train randomized 6800 congestive heart failure patients (ejection fraction > or =45%) to a daily regimen of either digoxin or placebo. At 37 months average follow-up, patients in both groups had similar mortality. We determined the incremental costs associated with the use of digoxin in this high-risk population. METHODS AND RESULTS: Hospitalizations and medical costs were compared by using a societal perspective. Hospitalizations were assigned Medicare DRG codes by using descriptive information from the clinical trial. Digoxin use was assigned a cost by using the 1998 average wholesale price as reported by Red Book. On average, there were fewer hospitalizations in digoxin-treated patients. These patients had lower heart failure yet higher non-heart failure hospitalization costs than placebo patients. Digoxin therapy was cost saving versus placebo in only 27% of 1000 bootstrap samples using Medicare costs (mean costs 12,648 dollars vs. 12,362 dollars) and in 44% of samples using commercial carrier costs (mean costs 17,400 dollars vs. 17,306 dollars). How ever, digoxin was cost saving in >50% of samples for several higher-risk patient subgroups. CONCLUSIONS: The use of digoxin therapy versus placebo was associated with reduced hospitalizations. Moreover, the resulting cost-savings could cover the costs of this inexpensive therapy in selected subgroups of higher-risk patients. In the remainder, there is a modest cost associated with this therapy.

The role of the data coordinating center in the DIG trial.

The Digitalis Investigation Group (DIG) trial was a large simple trial (LST) begun in 1990 as a collaboration between the National Heart, Lung, and Blood Institute and the Department of Veterans Affairs (VA) Cooperative Studies Program (CSP). Its primary objective was to determine whether digitalis had beneficial, harmful, or no effect on total mortality in patients with congestive heart failure and an ejection fraction < or =0.45. The Perry Point VA CSP Coordinating Center served as the trial's data coordinating center (DCC). The DCC was involved in all phases of the study from planning and design, organization and start-up, and patient recruitment and follow-up through closeout, final analyses, and manuscript preparation. While DCC responsibilities for an LST are basically the same as for other multicenter randomized clinical trials, their size and the inclusion of many inexperienced research sites can add a complexity that the DCC must be prepared to handle from the beginning. This paper describes the role of the DCC in the DIG trial.