Predict Postoperative Anemia of Patients: Nomogram Construction and Validation

Area of Science:

• Orthopedic Surgery
• Anesthesiology
• Hematology

Background:

• Blood loss is a significant complication following Total Knee Arthroplasty (TKA).
• Postoperative anemia after TKA can lead to adverse outcomes, including increased infection rates and prolonged hospital stays.
• Predictive tools for anemia can aid in patient blood management strategies.

Purpose of the Study:

• To identify independent preoperative risk factors for anemia in patients undergoing TKA.
• To develop and validate a predictive nomogram for postoperative anemia after TKA.

Main Methods:

• Retrospective analysis of 2,165 TKA patients (2015-2019).
• Logistic regression analysis to identify preoperative risk factors.
• Construction and validation of a nomogram using AUC, calibration curves, and decision curve analysis (DCA).

Main Results:

• Five independent predictors for anemia were identified: female sex, lower Body Mass Index (BMI), lower preoperative hemoglobin (Hb), higher preoperative Erythrocyte Sedimentation Rate (ESR), and simultaneous bilateral TKA.
• The nomogram demonstrated good predictive performance with AUCs of 74.6% (training) and 68.8% (validation).
• Calibration curves confirmed the nomogram's accuracy, and DCA indicated its clinical utility.

Conclusions:

• Female sex, lower BMI, lower preoperative Hb, higher preoperative ESR, and simultaneous bilateral TKA are significant risk factors for postoperative anemia (<9.0 g/dL) in TKA patients.
• A practical nomogram has been developed to predict the risk of postoperative anemia, aiding in patient management.
• The study provides evidence-level 4 for its findings regarding TKA-associated anemia risk factors.