Anemia predicts thromboembolic events, bleeding complications and mortality in patients with atrial fibrillation: insights from the RE-LY trial.

In this study, the authors performed a post-hoc analysis of the RE-LY study (a prospective, randomised trial that compared 2 doses of dabigatran with warfarin for stroke prevention in patients with atrial fibrillation) with the aim to assess the relationship between anaemia, cardiovascular events, bleeding complications and mortality.

The authors reviewed data from 18,113 patients included in the RE-LY study and observed that anaemia was present in 12% (2,125/17,796) of the population. Anaemia was defined according to the World Health Organization (WHO) criteria as a Hb < 13 g/dL in men and Hb < 12 g/dL in women. Because the primary study was not designed to assess the relationship between anaemia and outcomes, the incidence rates of the different outcomes were estimated as hazard ratios using Cox regression after adjustment for multiple confounders (e.g. age, creatinine level, cardiovascular risk factors). Anaemia was associated with a higher risk of both bleeding and thromboembolic complications, and with increased mortality. Interestingly, the incidence of events was lower in patients with transient anaemia than in patients in whom anemia was sustained. Although the RE-LY study was not designed to assess the relationship between anaemia and outcomes in anticoagulated patients, this post-hoc analysis confirms that anaemia is bad for our patients and that all efforts should be done to identify anaemia, assess the cause(s) of anaemia and optimise haemoglobin level in high-risk patients. – David Faraoni