Meta-Analysis of the Prognostic Impact of Anemia in Patients Undergoing Percutaneous Coronary Intervention.

Anemia is common in patients undergoing percutaneous coronary intervention (PCI), and current guidelines fail to offer recommendations for its management. This review aims to examine the relation between baseline anemia and mortality, major adverse cardiovascular events (MACE), and major bleeding in patients undergoing PCI. We searched MEDLINE and EMBASE for studies that evaluated mortality and adverse outcomes in anemic and nonanemic patients who underwent PCI. Data were collected on study design, participant characteristics, definition of anemia, follow-up, and adverse outcomes. Random effects meta-analysis of risk ratios was performed using inverse variance method. A total of 44 studies were included in the review with 230,795 participants. The prevalence of baseline anemia was 26,514 of 170,914 (16%). There was an elevated risk of mortality and MACE with anemia compared with no anemia-pooled risk ratio (RR) 2.39 (2.02 to 2.83), p <0.001 and RR 1.51 (1.34 to 1.71), p <0.001, respectively. The risk of myocardial infarction and bleeding with anemia compared with no anemia was elevated, pooled RR 1.33 (1.07 to 1.65), p = 0.01 and RR 1.97 (1.03 to 3.77), p <0.001, respectively. The risk of mortality per unit incremental decrease in hemoglobin (g/dl) was RR 1.19 (1.09 to 1.30), p <0.001 and the risk of mortality, MACE, and reinfarction per 1 unit incremental decrease in hematocrit (%) was RR 1.07 (1.05 to 1.10), p = 0.04, RR 1.09 (1.08 to 1.10) and RR 1.06 (1.03 to 1.10), respectively. The prevalence of anemia in contemporary cohorts of patients undergoing PCI is significant and is associated with significant increases in postprocedural mortality, MACE, reinfarction, and bleeding. The optimal strategy for the management of anemia in such patients remains uncertain.