Prognostic implications of anemia with or without chronic kidney disease in patients undergoing elective percutaneous coronary intervention

Abstract Background Little is known about the prognostic implications of anemia in patients undergoing elective percutaneous coronary intervention (PCI), especially when they have coexisting chronic kidney disease (CKD). Methods We identified 7299 patients who underwent elective PCI from the CREDO-Kyoto registry cohort-2. The primary outcome was 3-year major adverse cardiac events (MACE); composite of all cause death, heart failure hospitalization, and myocardial infarction. Results In total, 1466 patients (20.0%) had mild anemia (hemoglobin = 11.0–11.9 g/dL for women and 11.0–12.9 g/dL for men), and 740 patients (10.1%) had moderate-to-severe anemia (hemoglobin < 11.0 g/dL both for women and for men). Compared to the no-anemia group, cumulative incidence of MACE was significantly higher in the mild and moderate-to-severe anemia groups (7.9%, 20.1%, and 34.2%, respectively). The adjusted hazard ratios of mild and moderate-to-severe anemia versus no-anemia for MACE were 1.77 (95% confidence interval: 1.47–2.15) and 2.53 (95% confidence interval: 2.03–3.14), respectively. In a subgroup analysis, significantly higher risk for MACE was consistently observed with mild and moderate-to-severe anemia both in patients with and without CKD. The risk for MACE showed an accretive increment with exacerbation in either the renal function or anemia (interaction p < 0.001). Conclusions Even mild anemia was associated with significantly worse 3-year clinical outcomes in patients who underwent elective PCI. Coexisting CKD additively increased the risk for MACE in these patients.