Prognostic value of haemoglobin drop in patients with acute coronary syndromes

BACKGROUND The prognostic value of in-hospital haemoglobin drop in patients with acute coronary syndrome (ACS) undergoing invasive therapy remains insufficiently investigated. MATERIALS AND METHODS This observational study included 3838 patients with ACS with admission and in-hospital nadir haemoglobin values available. Haemoglobin drop was defined as a positive difference between admission and nadir haemoglobin values. The primary endpoint was one-year all-cause mortality. RESULTS In-hospital haemoglobin drop occurred in 3142 patients (82%). Patients were categorized into 4 groups: no haemoglobin drop (n = 696 patients), <3 g/dl haemoglobin drop (n = 2703 patients), 3 to <5 g/dl haemoglobin drop (n = 344 patients) and ≥5 g/dl haemoglobin drop (n = 95 patients). The primary endpoint occurred in 156 patients: 17 patients (2.5%) in the group with no haemoglobin drop, 81 patients (3.0%) in the group with <3g/dl haemoglobin drop, 37 patients (10.9%) in the group with 3 to <5 g/dl haemoglobin drop and 21 patients (22.2%) in the group with ≥5 g/dl haemoglobin (adjusted hazard ratio [HR] = 1.30, 95% confidence interval 1.17 to 1.45; p < .001 for one g/dl haemoglobin drop). The association of haemoglobin drop with one-year mortality remained significant after exclusion of patients with in-hospital overt bleeding (adjusted HR = 1.27 [1.11-1.46]; p < .001 for one g/dl haemoglobin drop). The lowest haemoglobin drop associated with mortality was 1.23 g/dl in all patients (HR = 1.03 [1.02-1.04]) and 1.13 g/dl in patients without overt bleeding (HR = 1.03 [1.01-1.04]). CONCLUSIONS In patients with ACS, in-hospital haemoglobin drop was associated with higher risk of one-year mortality even in the absence of overt bleeding.