Aims: 

In patients with acute coronary syndromes (ACS), the negative impact of baseline haemoglobin levels on ischaemic events, particularly death, is well established, but the association with bleeding risk is less well studied. The aim of this study was to assess the impact of baseline haemoglobin levels on major bleeding complications.

Methods and results: 

Pooled analysis of OASIS 5 and 6 data involving 32 170 patients with ACS with and without ST-segment elevation was performed. The association between baseline haemoglobin and major bleeding or ischaemic events was examined using multiple regression model. Main outcome measures were 30-day rates of major bleeding, death, and death/myocardial infarction (MI) analysed according to baseline haemoglobin levels. Baseline haemoglobin level independentlypredicted the risk of overall, procedure-related, and non-procedure-related major bleedings at 30 days [odds ratio (OR) 0.94, 95% CI 0.90–0.98; OR 0.94, 95% CI 0.90–0.99; and OR 0.89, 95% CI 0.83–0.95, respectively, per 1g/dL haemoglobin increment above 10 g/dL]. In addition, a curvilinear relationship between baseline haemoglobin levels and death at 30 days was observed with a 6% decrease in the risk for every 1g/dL haemoglobin increment above 10g/dL up to 15.9g/dL (OR 0.94, 95% CI 0.90–0.98) and a 19% increase above this value (OR 1.19, 95% CI, 0.98–1.43). A similar relationship for the composite outcome of death/MI was observed.

Conclusion: 

A low baseline haemoglobin level is an independent predictor of the risk of major bleeding in ACS as well as of the risk of death and death and MI. Among other predictors of bleeding risk, baseline haemoglobin should be taken into account in patients presenting with ACS (Fig 1).