Digoxin use and risk of mortality in hypertensive patients with atrial fibrillation.

BACKGROUND

Digoxin is widely used for rate control of atrial fibrillation. However, recent studies have reported conflicting results on the association of digoxin with mortality when used in patients with atrial fibrillation. Moreover, the relationship of digoxin use to mortality in hypertensive patients with atrial fibrillation has not been examined.

METHODS AND RESULTS

All-cause mortality was examined in relation to in-treatment digoxin use in 937 hypertensive patients with ECG left ventricular hypertrophy in atrial fibrillation at baseline (n = 134) or who developed atrial fibrillation during follow-up (n = 803), randomly assigned to losartan or atenolol-based treatment, in post-hoc analysis of a substudy of the Losartan Intervention For Endpoint Reduction in hypertension (LIFE) trial. During 4.7 ± 1.1 years of mean follow-up, 167 patients died (17.8%) and 372 (39.7%) were treated with digoxin. In univariate Cox analyses, in-treatment digoxin use, entered as a time-varying covariate, was associated with a 61% higher risk of dying (hazard ratio 1.61, 95% confidence interval 1.18-2.19, P = 0.003). After adjusting for other univariate predictors of death in this population, including age, diabetes, history of ischemic heart disease, stroke, or heart failure, baseline Cornell product, QRS duration, heart rate, serum glucose, creatinine and high-density lipoprotein cholesterol, and a propensity score for digoxin use entered as standard covariates, and for in-treatment heart rate, pulse pressure, and Sokolow-Lyon voltage treated as time-varying covariates, digoxin use was no longer a significant predictor of mortality (hazard ratio 1.04, 95% confidence interval 0.73-1.48, P = 0.839).

CONCLUSION

In hypertensive patients with ECG left ventricular hypertrophy with existing or new atrial fibrillation, digoxin use is not associated with a significantly increased risk of all-cause mortality after adjusting for other independent predictors of death and for the factors associated with the propensity to use digoxin in this population. These findings suggest that factors other than digoxin use may account for the increased mortality found with digoxin use in some studies.