Section Chief, Transfusion Medicine University of Utah Salt Lake City, Utah, United States
Background/Case Studies: Background/Case Studies: Transfusion related acute lung injury (TRALI) is the second leading cause of death related to transfusion. Several studies have reported TRALI rates, but these data have not been synthesized. The aim of this study was to use meta-analysis to estimate reported TRALI rates by blood component.
Study
Design/Methods: Study
Design/Methods: A literature search of Medline and Embase databases was conducted by a medical research librarian to identify relevant articles. Article review and data extraction were done by two researchers. Only articles published after 1990 were included. The number of TRALI cases were determined for each blood component (red blood cells (RBC), platelets (PLT), and plasma (FFP)) and calculated incidence rates per 100,000 blood components transfused. FFP and PLT must have used at least one modern TRALI donor restriction strategy to be included. Sources of heterogeneity were examined using meta-regression, including: leukoreduction, TRALI definition provided, the use of negative HLA antibody testing to include previously pregnant individuals, pathogen reduction, and population studied.
Results/Findings: Results/Findings: Fifty-six studies were included in the meta-analysis with nearly 150 million blood components transfused. RBCs had the highest number of studies (n=51) included in the meta-analysis, followed by PLTs (n=21) and FFP (n=18). The rate point estimate of TRALI was highest for FFP at 1.1 cases per 100,000 (95% CI: 0.5-1.9). This was followed by PLTs (0.9/100k, 95% CI: 0.4-1.6) and RBCs (0.7/100k, 95% CI: 0.5-1.0) (Table 1). The proportion of variation due to between-study variation was high (I2=87-94%), but the magnitude of the variation was not substantial. Studies that used HLA antibody testing to qualify previously pregnant individuals to donate showed significantly higher rates of TRALI in PLTs compared to those that only used male only and/or never pregnant females as donors (p < 0.01). Conclusions:
Conclusion: Meta-analysis of numerous studies showed the reported incidence of TRALI was approximately 1 in 100,000 for each blood component when accounting for modern TRALI risk mitigation strategies. As with other non-infectious adverse events related to transfusion, passive surveillance may underestimate the true rate of TRALI. Future studies using active surveillance may further improve this estimate.
Importance of research: TRALI is the second leading cause of mortality related to blood transfusion. Estimates of its incidence from individual studies are quite varied, as are the study characteristics. We previously performed a scoping review of the epidemiology of TRALI, which helped us carefully determine whether a meta-analysis was feasible. We have now completed that meta-analysis. Obtaining a good estimate of TRALI incidence can help with future research efforts aimed at reducing the incidence of TRALI.
