Association between anemia and mortality in patients with acute coronary syndrome treated with percutaneous coronary intervention and contemporary lipid-lowering therapy

Despite a clear correlation between anemia and mortality in patients with the acute coronary syndrome (ACS), anemia as a mortality predictor in patients with ACS-receiving early invasive strategy and contemporary lipid-lowering therapy has not been examined. Therefore, we aimed to evaluate the association between anemia and mortality in ACS patients treated with acute revascularization and contemporary lipid-lowering treatment. This was a post-hoc study of the Heart Institute of Japan-Proper level of Lipid-Lowering with Pitavastatin and Ezetimibe in acute coronary syndrome study, in which ACS patients with dyslipidemia were randomized to receive either pitavastatin and ezetimibe or pitavastatin monotherapy. The success rate of primary percutaneous coronary intervention (PCI) was 95.2%. Eligible patients were divided into two groups: patients with anemia (anemia group) or without anemia (non-anemia group). Anemia was defined using the World Health Organization definition hemoglobin < 12 g/dL for women and < 13 g/dL for men. We compared the mortality between the two groups using propensity scores derived from 17 baseline variables. We identified 1721 eligible patients, including 420 (24.4%) in the anemia group and 1301 (75.6%) in the non-anemia group. One-to-one propensity score-matching created 381 pairs. Both unmatched and matched analyses found significantly high mortality in the anemia group compared to the non-anemia group (unmatched 12.3% vs. 3.8%, log-rank p < 0.01; matched 11.5% vs. 6.3%, log-rank p = 0.01). In ACS patients treated with an early invasive strategy era with a high PCI success rate and concurrent contemporary lipid-lowering management, all-cause mortality was still significantly higher in anemic patients than in non-anemic patients.