Red blood cell transfusion does not increase risk of venous or arterial thrombosis during hospitalization

Abstract

Previous observational studies suggest associations between red blood cell (RBC) transfusion and risk for arterial or venous thrombosis. We determined the association between thrombosis and RBC transfusion in hospitalized patients using the Recipient Database from the National Heart Lung and Blood Institute (NHLBI) Recipient Epidemiology and Donor Evaluation Study-III. A thrombotic event was a hospitalization with an arterial or venous thrombosis ICD-9 code and administration of a therapeutic anticoagulant or antiplatelet agent. Patients with history of thrombosis or a thrombosis within 24 hours of admission were excluded. A proportional hazards regression model with time-dependent covariates was calculated. Estimates were adjusted for age, sex, hospital, smoking, medical comorbidities, and surgical procedures. Of 657 412 inpatient admissions, 67 176 (10.2%) received at least one RBC transfusion. Two percent (12927) of patients experienced a thrombosis. Of these, 2587 developed thrombosis after RBC transfusion. In unadjusted analyses, RBC transfusion was associated with an increased thrombosis risk [HR = 1.3 (95% CI 1.23-1.36)]. After adjustment for surgical procedures, age, sex, hospital, and comorbidities, no association between RBC transfusion on risk of venous and arterial thrombosis was found [HR 1.0 (95% CI: 0.96-1.05)]. Thus, RBC transfusion does not appear to be an important risk factor for thrombosis in most hospitalized patients.

FIGURE 1

Study flow diagram. The definition of thrombosis includes venous and arterial thrombosis

FIGURE 2

A, Hazard ratio of arterial and venous thrombosis in relation to type of surgery. Surgical procedures were grouped by surgical subspecialty. Hazard ratios and 95% confidence intervals from Cox proportional hazards model adjusted for age, sex, hospital, transfusion, and other surgical procedures. The reference groups are patients without that surgical procedure. B, Hazard ratio of arterial and venous thrombosis in relation to medical comorbidities. Hazard ratios and 95% confidence intervals from Cox proportional hazards model adjusted for age, sex, hospital, transfusion, and surgical procedures. The reference groups are patients without that comorbidity

FIGURE 3

Association between RBC transfusion and arterial and/or venous thrombosis. Hazard ratios and P values from Cox proportional hazards model. *Cardiac, Vascular, Orthopedic, General, Otolaryngology, and Thoracic Surgery. ⁺⁺Comorbidities include arrhythmia, chronic heart failure, chronic lung disease, diabetes (complicated and uncomplicated), hypertension, liver disease, metastatic cancer, and renal failure