Chi G, et al. - Researchers analyzed if anemia presented as a risk factor for venous thromboembolism in acutely ill hospitalized medical patients and whether the presence of anemia could refine the risk assessment for prediction of venous thromboembolism, thereby adding incremental utility to a validated model. An independent connection was disclosed between anemia with a greater risk of symptomatic venous thromboembolism among acutely ill medical patients regardless of the provision of thromboprophylaxis. It was noted that the hemoglobin measurement improved risk stratification by the IMPROVE venous thromboembolism risk score.

Methods

• Randomization was carried out of 7,513 hospitalized medical patients to receive either betrixaban or standard-of-care enoxaparin for thromboprophylaxis.
• Baseline hemoglobin concentrations were collected from 6,861 patients with a follow-up of 77 days.
• A comparison was performed of the symptomatic venous thromboembolism events, including symptomatic deep vein thrombosis, pulmonary embolism, and venous thromboembolism-related mortality, between low hemoglobin and normal hemoglobin group (normal range: 12.5 to 17.0 g/dL for males and 11.0 to 15.5 g/dL for females).
• Experts determined the association between anemia and venous thromboembolism events by fitting a univariable and multivariable logistic regression model composed of thromboprophylaxis and risk factors.
• In the IMPROVE risk assessment model, venous thromboembolism risk refinement by hemoglobin measurement was assessed.

Results

• Data shed light on the link between low hemoglobin at baseline with a greater risk of symptomatic venous thromboembolism (RR=1.94 [95% CI: 1.27-2.98]; p=0.002), symptomatic deep vein thrombosis (RR=2.29 [1.12-4.68]; p=0.019), and non-fatal pulmonary embolism (RR=2.63 [1.22-5.65]; p=0.010) but not venous thromboembolism-related mortality (RR=1.47 [0.71-3.04]; p=0.30).
• History of previous venous thromboembolism, intensive or coronary unit admission and D-dimer, low hemoglobin (as a categorical or continuous variable) exhibited a correlation with an increased tendency of venous thromboembolism (adjusted OR=1.71 [1.09-2.69]; p=0.020) after adjusting for thromboprophylaxis.
• Furthermore, low hemoglobin appeared to improve the risk discrimination and reclassification after inclusion in the IMPROVE model.