Aims: Anaemia is a common comorbidity in chronic heart failure (CHF). The predictors of new onset anaemia (NOA) and its long-term prognostic value, particularly in patients treated with beta-blockers, are not known.
Methods and results: In COMET, 3029 patients with CHF in NYHA II-IV and EF <35% were randomized to carvedilol or metoprolol tartrate and were followed for an average of 58 months. Plasma haemoglobin (Hb) concentrations were measured at a central laboratory at randomization, at four monthly intervals for the first year and annually thereafter. According to WHO criteria, anaemia was defined when Hb measured <13 g/dL for men and <12 g/dL for women. We considered anaemia to be severe when Hb <11.5 g/dL for men and <10.5 g/dL for women. The baseline mean Hb was 14.2 +/- 1.5 g/dL (n = 2996) and 15.9% of patients had anaemia (males, 16.0%; females, 15.2%). At baseline, severe anaemia was found in 3.3% of patients (males, 3.6%; females, 2.0%). During the study, all-cause mortality (RR 1.47) death or hospitalization (RR 1.28), and heart failure hospitalization (RR 1.43, all P < 0.0001) were higher in anaemic when compared with non-anaemic patients. In patients without anaemia at baseline, at the end of the study, the cumulative frequency of NOA was 28.1% in males and 27.0% in females. NOA increased over time from 14.2% at year 1 to 27.5% at year 5. Predictors of NOA were: higher age, diuretic dose, creatinine (all P < 0.0001), higher serum potassium, lower serum sodium, body mass index, and use of aldosterone antagonists, carvedilol, and digitalis (all P < 0.03). Treatment with carvedilol (vs. metoprolol tartrate) was associated with a 24% increased risk to develop NOA (P = 0.0047), but not severe anaemia (P = 0.18). Patients with a Hb decrease of >3 g/dL (RR 3.37, P < 0.0001) or of 2.0-3.0 g/dL (RR 1.47, P = 0.011) from baseline had an increased subsequent mortality when compared with patients having Hb increases of 0-1.0 g/dL.
Conclusion: In stable ambulatory CHF patients, development of NOA is frequent and can be predicted by a set of clinical variables. Decreases in Hb over time relate to future increased morbidity and mortality.