The safety and efficacy of warfarin remain unclear in patients aged ≥70 years of age with atrial fibrillation (AF) and there are sparse data on the effect of long-term anticoagulation on mortality in these patients. A propensity-matched study of the association of warfarin and outcomes in older adults with AF was therefore conducted to examine this issue.

Of the 4060 patients (mean age 65 years, range 49 to 80) in the Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) trial, 2248 (55%) were aged 70 to 80 years, 1901 of whom were on warfarin. The propensity score for warfarin use, estimated for each of the 2248 patients, was used to match 227 of the 347 patients not on warfarin to 616 patients on warfarin who were balanced in 45 baseline characteristics.

The following findings were reported:

• All-cause mortality occurred in 18% and 33% of matched patients receiving and not receiving warfarin, respectively, during up to 6 years (mean 3.4) of follow-up (hazard ratio when warfarin use was compared non-use = 0.58, 95% CI, 0.43 to 0.77, p<0.001).

• All-cause hospitalisation occurred in 64% and 67% of matched patients receiving and not receiving warfarin, respectively (0.93, 0.77 to 1.12, p = 0.423).

• Ischaemic stroke occurred in 4% and 8% of matched patients receiving and not receiving warfarin, respectively (0.57, 95% CI 0.31 to 1.04, p = 0.068).

• Major bleeding occurred in 7% and 10% of matched patients receiving and not receiving warfarin, respectively (0.73, 95% CI 0.44 to 1.22, p = 0.229).

The researchers conclude from this propensity-matched cohort of septuagenarian patients with AF, that warfarin was associated with decreased mortality but had no association with hospitalisation or major bleeding. They suggest these findings are important because the incidence of AF increases with age yet warfarin may be underused in this population based on concern for adverse effects and outcomes; and the incidence of AF is projected to increase with ageing of the population.