Impact of anemia on long-term ischemic events and bleeding events in patients undergoing percutaneous coronary intervention: a system review and meta-analysis.

BACKGROUND: Data focused on the ischemic events and bleeding events are still limited. We systematically reviewed the current available literature to investigate whether anemia increase incidence of long-term ischemic events and long-term bleeding events in patients undergoing PCI. METHODS: PubMed and Embase were searched for case-control studies regarding the impact of anemia on long-term outcomes in patients undergoing percutaneous coronary intervention (PCI). The primary outcome was long-term ischemic events and long-term bleeding events. Mantel-Haenszel method with random effects model or fixed effects model was used to calculate pooled odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Seventeen studies involving 68,528 patients (17,123 anemic patients and 51,405 non-anemic patients) were included. Pooled analysis suggested that anemic patients were at higher risk for long-term composite ischemic events (OR: 1.95, 95% CI, 1.21-3.14, P<0.01, I(2)=84%), long-term reinfarction (0R: 1.63, 95% CI, 1.16-2.28, P<0.01, I(2)=82%) and long-term bleeding events (OR: 2.89, 95% CI, 1.68-4.98, P<0.001, I(2)=89%). Anemia was also associated with long-term mortality (OR: 3.20, 95% CI, 2.72-3.75, P<0.01, I(2)=65%) and major adverse cardiac events (MACE) (OR: 2.06, 95% CI, 1.48-2.86, P<0.01, I(2)=91%). CONCLUSIONS: Anemic patients undergoing PCI are at higher risk for both long-term ischemic events and bleeding events, and also at higher risk for long-term mortality and MACE. There's a need for further clarification and consistency regarding dosage, timing and duration of antithrombotic therapy for the prevention of ischemic events and bleeding events in anemic patients.