Impact of Preoperative Anemia Severity on Primary Total Hip Arthroplasty Outcomes

Preoperative anemia (POA) is a significant predictor for adverse outcomes in primary total hip arthroplasty (THA). Current literature has studied POA stratified by severity. This study aims to find a threshold preoperative hemoglobin (Hb) value for increased risk of adverse outcomes in THA.This is a retrospective analysis of primary THA patients with preoperative Hb values from 2014 to 2021 from an academic orthopedic specialty hospital. Demographics, surgical data, and postoperative outcomes were collected. Patients without preoperative Hb values within the electronic health record system or values acquired30 days preoperatively were excluded. Patients were grouped based on POA severity using World Health Organization criteria. Secondary analysis using discrete preoperative Hb values was performed. P-values were calculated using analysis of variance/Kruskal-Wallis and chi-squared/Fisher's exact testing with P.05 considered significant.A total of 1347 patients were included: 771 (57.2%) patients with POA and 576 (42.8%) with normal preoperative Hb. In the POA group, 292 (37.9%) were mild, 445 (57.7%) moderate, and 34 (4.4%) severe. Increased length of stay was seen in moderate (3.9 ± 4.3 vs 2.4 ± 2.1, P.001) and severe (5.0 ± 3.4 vs 2.4 ± 2.1, P.0001) groups compared to control. The severe group had higher 90-day readmission and revision rates compared to control. Analysis by discrete Hb values showed increased length of stay in Hb values11 g/dL and a greater proportion of patients with Hb values12 g/dL were discharged to skilled nursing facilities.Patients with preoperative Hb12 g/dL should be assessed for other risk factors that may predispose them to postoperative complications. Further investigation is warranted to develop more robust perioperative management strategies for POA patients undergoing THA.Retrospective Cohort Study.