Incidence and predictors of blood transfusions in one-stage bilateral total hip arthroplasty: a single center prospective cohort study

Introduction The safety of performing one-stage bilateral total hip arthroplasty (THA) remains controversial among the orthopedic community. The aim of the present study was to determine the incidence and predictors of blood transfusions in one-stage bilateral THA performed in a high-volume single center. Patients and methods Patients undergoing one-stage bilateral THA between 2015 and 2017 were included. The following data were collected from the hospital medical records: age, body mass index (BMI), American Society of Anaesthesiologists (ASA) score, smoking habit, comorbidities, preoperative serum creatinine, serum iron, ferritin, C-reactive protein (CRP), and hemoglobin (Hb). The Hb levels at postoperative day 1 and 3 were also collected. Results A total of 367 patients with a mean age of 56.1 years (range, 32-79) were included. Forty-eight (13%) patients were transfused with a mean number of 1.6 blood units per patient. In non-transfused patients, the average Hb drop was 3.6 (SD +/- 1) g/dL and 4.9 g/dL (SD +/- 1.3) at postoperative day 1 and day 3, respectively. The average preoperative Hb level was 14.64 (SD +/- 1.21) g/dL. In the univariate logistic regression, the following variables were predictive factors for transfusions: male gender (OR 0.447; P = 0.01), preoperative hemoglobin level (OR 0.622; P = 0.001), preoperative ferritin level (OR 0.995; P = 0.016), BMI (OR 0.837; P = 0.001), cardiopathy (OR 3.534; P = 0.046), preoperative anaemia (OR 10.54; P = 0.011). In the multivariate logistic regression only preoperative hemoglobin level (OR 0.666; P = 0.01), and BMI (OR 0.868; P = 0.007) were statistically significant. Conclusions The incidence of blood transfusions after one-stage bilateral THA is low in non-anemic patients operated on at a high-volume arthroplasty center. The main predictors of blood transfusions are preoperative Hb level and BMI.