Warfarin Treatment and All-Cause Mortality in Community-Dwelling Older Adults With Atrial Fibrillation: A Retrospective Observational Study

Editor's Note: Summary based on Pilotto A, Gallina P, Copetti M, et al. Warfarin treatment and all-cause mortality in community-dwelling older adults with atrial fibrillation: a retrospective observational study. J Am Geriatr Soc 2016;64:1416-24. For accompanying commentary, please see the associated Expert Analysis.

Study Question: What is the effect of warfarin therapy on all-cause 2-year mortality in older adults with atrial fibrillation and low, moderate, or high risk of death based on the Multidimensional Prognostic Index (MPI)?

Methods: The authors studied 1827 community-dwelling adults ≥65 years of age (mean 84.4 ± 7.1 years, 64.3% female) with atrial fibrillation. Multidimensional geriatric assessment was performed at baseline and subjects were classified as being at low, moderate, or high mortality risk using the MPI, a validated tool for assessing prognosis in older adults. Factors incorporated into the assessment tool include age, sex, comorbidity, cognitive status, mobility, functional disability, pressure sore risk, and social support. The association between warfarin treatment and mortality was examined using multivariate and propensity-adjusted Cox regression models controlling for age, sex, all geriatric assessment domains, comorbid conditions, and medications.

Results: Overall, 705 subjects (38.6%) were classified as low risk, 634 (34.7%) were moderate risk, and 488 (26.7%) were high risk. Age was similar in the three groups, but the proportion of men increased as a function of risk category (p < 0.001). Use of warfarin declined from 53.9% in the low-risk group to 38.6% in the intermediate-risk group, and 35.5% in the high-risk group (p < 0.001). As expected, 1-, 2-, and 3-year mortality rates increased progressively by risk category. However, in the fully-adjusted multivariate propensity score models, warfarin treatment was associated with a hazard ratio for 2-year mortality of 0.65 (95% CI 0.50-0.82) in the low risk group, 0.68 (95% CI 0.55-0.85) in the moderate risk group, and 0.55 (95% CI 0.49-0.67) in the high risk group (all p < 0.001).

Conclusion: Community-dwelling older adults with atrial fibrillation benefited from anticoagulation with respect to 2-year all-cause mortality, regardless of poor health and functional condition.

References

  1. Pilotto A, Gallina P, Copetti M, et al. Warfarin treatment and all-cause mortality in community-dwelling older adults with atrial fibrillation: a retrospective observational study. J Am Geriatr Soc 2016;64:1416-24.

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