CRP and chronic obstructive pulmonary disease: The independent risk factors of postoperative DVT in patients with femoral fracture included perioperative RBC infusion (P = 0.012), multiple traumas (P = 0.016), time from trauma to surgery > 7d (P = 0.002), time to start anticoagulation after surgery (P = 0.003), nephropathy (P = 0.015), hypoproteinemia (P = 0.000), COPD (P = 0.001), age (P = 0.002), the number of comorbidity (P = 0.000) and CRP level on day 3 after surgery (P = 0.005).