Predisposing factors for allogeneic blood transfusion in patients with ankylosing spondylitis undergoing primary unilateral total hip arthroplasty: a retrospective study

BACKGROUND: The transfusion rate is relatively high in patients with ankylosing spondylitis (AS) undergoing total hip arthroplasty (THA). However, relevant studies focusing on the predisposing factors for transfusion with a large sample size are lacking. This study aimed to investigate the incidence of and risk factors for allogeneic blood transfusion in patients with AS undergoing primary unilateral THA. METHODS: This retrospective study included 331 patients with AS who underwent primary unilateral THA between 2011 and 2021. Relevant parameters were collected through a chart review. Multivariate logistic regression analysis was conducted to identify possible factors associated with perioperative allogeneic blood transfusion. RESULTS: A total of 113 (34.1%) patients received perioperative allogeneic blood transfusions. Factors related to receiving an allogeneic blood transfusion included prolonged operative duration (odds ratio [OR] per 10 min = 1.139, P = 0.047), increased estimated intraoperative blood loss (OR per 100 mL = 1.348, P < 0.001), and increased postoperative drainage volume (OR per 100 mL = 1.235, P = 0.024). A higher body mass index (BMI) (OR = 0.914, P = 0.012), perioperative tranexamic acid (TXA) use (OR = 0.166, P < 0.001), and a higher preoperative hemoglobin level (OR per 1 g/dL = 0.744, P = 0.004) decreased the risk of transfusion. CONCLUSIONS: In patients with AS undergoing THA, prolonged operative duration, increased estimated intraoperative blood loss, and increased postoperative drainage volume were found to be risk factors for transfusion, whereas a higher BMI, perioperative TXA use, and a higher preoperative hemoglobin level were protective factors. These results may aid in developing a better perioperative management strategy, ultimately reducing the need for transfusion.