Anemia in patients with atrial fibrillation (AF) is associated with major bleeding and lower time in therapeutic range (TRR), according to results published in the European Heart Journal. The results also indicated that oral anticoagulation (OAC) was associated with an increased risk in major bleeding with no reduction in risk of stroke/thromboembolism (TE) in patients with moderate/severe anemia.

The study included Danish participants who were diagnosed with AF from 1997 to 2012 from administrative registry databases (n = 18,734). The researchers used multiple Cox regression analyses to estimate hazard ratios and to compute standardized absolute 1-year risks of stroke/TE and major bleeding.

Out of all participants, 20% (n = 3796) had mild anemia (Hb 6.83-7.45 mmol/L for women and Hb 6.83-8.03 mmol/L for men) and 14% (n = 2562) had moderate/severe anemia (Hb <6.83 mmol/L for women and men).

The researchers found that moderate/severe anemia was associated with an increased risk of major bleeding and 9.1% lower median TTR compared with participants with no anemia.

The use of OAC was associated with a reduced risk of stroke/TE for participants without anemia (standardized absolute 1-year difference -2.5%; 95% CI, -3.8 to -1.7) and for participants with mild anemia (standardized absolute 1-year difference -2.3%; 95% CI, -3.8 to -0.8) but not for participants with moderate/severe anemia (standardized absolute 1-year difference 0.3%; 95% CI, -1.8 to 2.8; P =.01). OAC was associated with a 5.3% (95% CI, 2.1-8.7%) increased standardized absolute risk of major bleeding among those with severe anemia.

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“Caution with OAC might be warranted among patients with AF and moderate/severe anaemia, who require careful evaluation of the balance between harm or benefit of treatment,” wrote the researchers.

Reference

Bonde AN, Blanche P, Staerk L, et al. Oral anticoagulation among atrial fibrillation patients with aneamia: an observational cohort study [published online April 1, 2019]. Eur Heart J. doi:10.1093/eurheartj/ehz155