Identification of Data-Driven Preoperative Hemoglobin Strata That Predict the Likelihood of Blood Transfusion and the Risk of Major Complications and Prosthetic Joint Infection After Total Hip Arthroplasty

Abstract

Introduction: Preoperative anemia is an independent risk factor of complications after primary total hip arthroplasty (THA). Currently used hemoglobin thresholds are not developed for risk stratification of arthroplasty patients and do not provide surgery-specific information on postoperative complication risk. Thus, we aimed to calculate THA-specific preoperative hemoglobin strata that observe the likelihood of 90-day blood transfusion and determine whether these strata are associated with increased risk of 90-day complications and 2-year prosthetic joint infection (PJI). Methods: A retrospective cohort analysis identified 56,101 patients who underwent primary THA from 2013 to 2022. Using the lowest hemoglobin value for each patient one month before THA, stratum-specific likelihood ratio (SSLR) analysis calculated sex-based hemoglobin strata associated with the likelihood of 90-day postoperative blood transfusion. Propensity score matching was performed. Incidence rates and risk of 90-day major complications and 2-year PJI were observed for each identified preoperative hemoglobin stratum. Results: SSLR analysis identified five male (strata, likelihood ratio [<10.4 g/dL, 12.5; 10.5 to 11.4 g/dL, 8.0; 11.5 to 12.4 g/dL, 2.4; 12.5 to 13.4 g/dL, 1.3; 13.5 to 13.9 g/dL, 0.5]) and five female (<8.9 g/dL, 10.7; 9.0 to 10.9 g/dL, 4.0; 11.0 to 11.4 g/dL, 2.0; 12.0 to 12.9 g/dL, 1.0; 13.0 to 13.4 g/dL, 0.6) preoperative hemoglobin strata associated with varying likelihoods of 90-day blood transfusion after THA. After matching in both male and female cohorts, as the calculated preoperative hemoglobin strata decreased, the relative risk of overall 90-day major complications and 2-year PJI increased incrementally (all P < 0.05). Conclusion: SSLR analysis established THA-specific sex-based preoperative hemoglobin strata that observe the likelihood of 90-day blood transfusion and predict the risk of 90-day medical complications and 2-year PJI. These strata are a first of their kind in THA research. While preoperatively optimizing patients, we recommend using these hemoglobin thresholds to help guide decisions on presurgery anemia optimization and to reduce the need for postoperative blood transfusion. Level of Evidence: Level III.