LAUSR

BACKGROUND The vast majority of patients undergoing hemodialysis (HD) are anemic. The severity of anemia in these patients may influence the postoperative outcomes and the durability of vascular access. Thus, the purpose of this study is to assess the association between anemia and adverse outcomes in patients undergoing HD access placement [arteriovenous grafts (AVG) and fistula (AVF)]. METHODS Patients with chronic kidney disease (CKD) Stages IV and V recorded in the VQI-Hemodialysis database between 2011 and 2017 were included. Patients were divided into 3 study groups based on preoperative hemoglobin levels (Hgb): normal/mild anemia (Hgb: Females>10 g/dL, Males>12 g/dL), Moderate anemia (Hgb: Females: 7-9.9 g/dL, Males: 9-11.9 g/dL) and severe anemia (Hgb: Females<7 g/dL, Males<9 g/dL). Multivariable logistic and cox-regression analysis were implemented to evaluate the association between anemia and 30-day mortality and primary patency (PP) at 1 year. RESULTS A total of 28,000 patients undergoing HD access surgery were identified [normal/mild (42%), moderate (49%) and severe (9%) anemia]. Postoperative bleeding (2.1% vs. 2.2% vs. 2.2%) and 30-day outcomes including swelling (0.4% vs. 0.5% vs. 0.7%) and wound infection (0.4% vs. 0.3% vs. 0.1%) were similar in mild/normal, moderate and severe anemia groups, respectively (All P>0.05). However, 30-day mortality was significantly higher in patients with severe anemia compared to normal/mild and moderate anemia (2.1% vs. 1.1% and 1.1%, P<0.001). After adjusting for potential confounders, severe anemia was associated with 90% higher risk of 30-day mortality [OR(95%CI): 1.90(1.20-3.00), P=0.006] and 17% increase in PP loss at 1 year [aHR(95%CI): 1.17(1.02-1.35), P=0.01] compared to the normal/mild anemia group. However, no significant difference was seen between normal/mild and moderate anemia. CONCLUSION In this large study of patients undergoing HD access placement, severe anemia was associated with 90% increased risk of 30-day mortality and 17% increased risk of loss of primary patency compared to those with normal/mild anemia. Management of severe anemia prior to surgery might be indicated to reduce operative mortality and improve the durability of HD access.