3.1 Effect of anaemia on outcomes

3.1.1 Acute coronary syndrome

Evidence statements for Acute coronary syndrome

Evidence Statements – acute coronary syndrome
ES1.1	In patients with ACS, anaemia is independently associated with all-cause mortality.
ES1.2	In patients with ACS, the effect of anaemia on cardiovascular mortality is uncertain.
ES1.3	In patients with NSTE-ACS, anaemia is independently associated with MI and recurrent ischaemia.		NA

ACS, acute coronary syndrome; ES, evidence statement; MI, myocardial infarction; NSTE-ACS, non-ST segment elevation acute coronary syndrome

=A; =B; NA,not applicable (see Table 2.1)

Twelve prospective cohort studies (Level II) were included for the ACS population; 10 provided evidence for mortality,^15-24 and 4 for composite or cardiovascular outcomes.^21,22,25,26

A fair-quality study showed that anaemia, as defined by WHO, was an independent risk factor for all- cause mortality and death due to progressive heart failure in patients diagnosed with acute myocardial infarction (MI), but was not an independent risk factor for sudden cardiac death.¹⁵ In a study by Valeur et al, WHO-defined anaemia was an independent risk factor for mortality in patients with ACS with heart failure only.¹⁶ This study also showed that a one standard deviation increase in Hb resulted in a significantly decreased risk of all-cause mortality (12% reduction) and death due to progressive heart failure (20% reduction). Most of the analyses showed that Hb concentrations below 150 – 160 g/L were a significant independent risk factor for 30-day mortality.¹⁶ In addition, a 10 g/L decrease in Hb significantly increased the risk of mortality.

In summary, the results were generally consistent across all included studies, with most suggesting that anaemia is an independent risk factor for mortality and adverse cardiovascular outcomes. Evidence from one large good-quality study suggests that any decrease in baseline Hb concentration is associated with an increased risk of mortality.¹⁹