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

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.