Abnormal haemoglobin levels in acute coronary syndromes

Anaemia is an adverse prognostic marker in acute coronary syndromes (ACS), but the epidemiology of abnormal haemoglobin levels in such patients is uncertain.

To investigate the prevalence, nature and predictors of abnormal haemoglobin levels in ACS patients at admission.

Observational study.

All emergency admissions from January to April 2005 were assessed within 24-48 h of hospital admission. ACS patients (unstable angina, non-ST-elevation or ST-elevation myocardial infarction) were enrolled (n = 320, 190 men). Clinical information was recorded.

Overall, 71% had unstable angina; 18% non-ST-elevation myocardial infarction (MI), and 11% ST-elevation MI. Mean +/- SD haemoglobin was 14.3 +/- 1.7 g/dl in men and 13.2 +/- 1.5 g/dl in women. Abnormal haemoglobin was more common in men (65, 34%) than in women (34, 22%) (p = 0.013). Anaemia (haemoglobin <13 g/dl in men, or <12.0 g/dl in women) was recorded in 35 (18%) men and 24 (18%) women. All had admission haemoglobin >8 g/dl, and anaemia was usually normocytic. Multivariate predictors of anaemia (OR, 95%CI) were age (1.07, 1.04-1.1) and serum albumin (0.90, 0.81-1.00). Elevated haemoglobin (>16 g/dl) was recorded in 30 (16%) men and 4 (3%) women (p < 0.01), and was more common in ST-elevation MI patients (26%) than in unstable angina or non-ST elevation MI patients (9%) (p = 0.005). In patients who underwent invasive management with a post-procedure haemoglobin the following day (n = 85), 15 (18%) new cases of anaemia were detected. Admission duration correlated with haemoglobin (p < 0.01), creatinine (p < 0.01), troponin I (p < 0.01) and C-reactive protein (p < 0.01). Anaemia was more common in those who died in hospital (3, 60%) than in those who survived (56, 18%) (adjusted p = 0.0135).

Abnormal haemoglobin levels were common in our ACS admissions. Anaemia was generally mild. Increasing age and interventional management were associated with anaemia, which in turn was associated with adverse in-hospital outcomes. Interventions to prevent and detect anaemia in this setting merit prospective testing.