Lack of Evidence of Increased Mortality Among Patients With Atrial Fibrillation Taking Digoxin: Findings From Post Hoc Propensity-Matched Analysis of the AFFIRM Trial
Does digoxin increase the risk of death in patients with atrial fibrillation (AF)?
A post-hoc analysis of the AFFIRM (Atrial Fibrillation Follow-up Investigation of Rhythm Management) database identified 878 patients (mean age 70 years) with AF who received digoxin and 878 patients matched for 59 characteristics who did not receive digoxin. The primary outcome of the study was all-cause mortality.
During a mean follow-up of 3.4 years, there was not a significant difference in mortality between the patients taking digoxin (14%) and the matched patients who were not taking digoxin (13%). There also was not a significant difference between the matched sets of patients in all-cause hospitalizations or nonfatal cardiac arrhythmias.
The authors concluded that digoxin does not increase the risk of death or hospitalization in patients with AF.
Conflicting conclusions between prior studies are neither uncommon nor surprising. However, one generally expects similar conclusions to emanate from analysis of the same database. Quite remarkably, a recent post-hoc analysis of the very same AFFIRM database analyzed in the present study (but by a different set of authors) concluded that digoxin was independently associated with a 35% higher risk of all-cause mortality (Whitbeck MG, et al., Eur Heart J 2012;Nov 27:[Epub ahead of print]). The fact that two analyses of the same database can arrive at directly opposite conclusions is a sobering demonstration of the limitations of post-hoc analyses.
Keywords: Follow-Up Studies, Digoxin, Cardiology, Hospitalization
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