The Epidemiology of Multiple Blood Component Transfusion

Abstract

Multicomponent transfusion, or the transfusion of two or more different blood products, has been poorly studied to date, as most of the existing literature has focused on the use of individual blood products. This is of concern as multicomponent transfusion recipients likely differ with respect to characteristics and health outcomes from patients transfused with only one type of blood component (e.g. greater illness severity). Consequently, available data on individual blood product use and outcomes may not be applicable to multicomponent transfused patients. This thesis project identified and synthesized existing literature on the epidemiology of multicomponent transfusion in hospital inpatients, as well as the characteristics and outcomes of its recipients. Based on 37 observational studies, we found that the prevalence of multicomponent transfusion varied greatly by patient population, transfusion timeframe, and type of multicomponent transfusion being studied. The most common types of multicomponent transfusion across the 37 studies were co-transfusions of red blood cells (RBCs) and platelets, and co-transfusions of RBCs and plasma. Multicomponent transfusion was found to be associated with several negative health outcomes, however this was based on low quality evidence due to lack of control for confounding by indication. Our systematic review on multicomponent transfusion identified several knowledge gaps, including the need for studies focusing on patients with hematological malignancies, and studies identifying patient characteristics predictive of multicomponent transfusion. To address areas of knowledge deficiency, and to characterize multicomponent transfusion locally at our own center, we designed and conducted a retrospective cohort study of adult, transfused hospital inpatients. Based on 55,719 transfused inpatient admissions at the Ottawa Hospital between 2007 and 2017, we calculated the overall prevalence of multicomponent transfusion to be 25.1% (95% CI: 24.7%, 25.5%). Similar to the findings of our systematic review, the prevalence varied greatly by patient type, transfusion timeframe, and type of multicomponent transfusion. In particular, in hematology patients, the prevalence of multicomponent transfusion was 51%. Other patient groups frequently receiving multicomponent transfusions at our institution were cardiac surgery, critical care, cardiology, vascular surgery, trauma, surgery, and internal medicine patients. Using multivariable regression analysis, we found that patient sex, age, and type were predictive of multicomponent transfusion requirement. Additionally, controlling for illness severity and burden, multicomponent transfusion was associated with increased odds of in-hospital mortality, institutional discharge compared to discharge home, and greater length of hospital stay compared to patients transfused with only RBCs. Given our findings that multicomponent transfusion recipients make up a large proportion of transfused hospital patients, and that they have poorer outcomes, it is of importance to continue characterizing these patients – and not only focus on patients receiving a single type of blood component – and to evaluate and monitor the appropriateness of multicomponent transfusion. Additionally, as transfusion practice and guidelines are known to vary from region to region, it is important to study multicomponent transfusion locally, as generalizing results from other studies and centers may not be appropriate. Obtaining robust information on multicomponent transfusion – including prevalence, predictors, and potential health consequences – can aid clinicians in their decision-making for patient blood management, potentially minimizing unnecessary patient exposure to blood products, and maximizing the use of transfusion alternatives and blood conservation methods.