Preoperative anemia and its severity are associated with postoperative deep vein thrombosis in lower limb trauma patients: a cohort study

Abstract

Background There is still lack of data on the relationship between the severity of preoperative anemia and postoperative deep vein thrombosis (DVT) following bone trauma. This study aimed to determine whether there is an association of varying degrees of anemia with postoperative DVT. Method Retrospective analysis of clinical data on patients who underwent surgery for traumatic fractures of the femur, pelvis, or acetabulum between May 2018 and December 2022. Data on demographics, complications, surgical and fracture-related data, preoperative laboratory indicators, anticoagulation were collected, patients were categorized based on their last preoperative hematocrit (HCT) results. Univariate analyses and multivariable analysis were used to identify the independent risk factors associated with DVT. Results Among the 284 cases with postoperative thrombosis, 61(21.5%) had no anemia before surgery, while 223(78.5%) had anemia before surgery. Among those with anemia, 65(29.1%) had mild anemia, and 158(70.9%) had moderate to severe anemia. Multivariable analysis results showed that age > 65 years (OR:2.761, 95%CI[1.673–4.557], p < 0.001), length of stay > 14 days (OR:1.683, 95%CI[1.175–2.410], p = 0.005), preoperative anticoagulation (OR:1.608, 95%CI[1.099–2.352], p = 0.015), anticoagulation after surgery > 24h (OR:1.865, 95%CI[1.221–2.848], p = 0.004), preoperative HCT ranging 33–30% and perioperative blood transfusion (OR:3.052, 95%CI[1.603–5.881], p = 0.001), and preoperative HCT < 27% and blood transfusion (OR:2.979, 95%CI[1.574–5.639], p = 0.001) were independent risk factors for postoperative DVT formation. The ROC curves showed that a preoperative HCT of 35.15% (AUC = 0.670, sensitivity = 64.6%, specificity = 61.2%) in males and 33.45% (AUC = 0.637, sensitivity = 63.7%, specificity = 60.2%) in females were the cut-off values for predicting postoperative DVT occurrence. Conclusions The risk of postoperative DVT increases with the severity of preoperative anemia in patients with bone trauma, and perioperative blood transfusion further increases the risk of DVT. Trial registration: ChiCTR2100049356.