Background: The purpose of this scoping review was to identify available sources of evidence on the epidemiology of transfusion-related acute lung injury (TRALI) and whether meta-analysis on the incidence of TRALI is feasible. TRALI is a serious complication and the second leading cause of death related to blood transfusion. Estimates of the incidence of TRALI would provide a useful benchmark for research to reduce TRALI.
Study design and methods: We searched the Medline, EMBASE, and PubMed databases for publications related to the incidence of TRALI and hemovigilance. We included all studies irrespective of language or country. Both full-text articles and conference abstracts were included. Participants of the studies must all have received a blood transfusion. Reviews and case studies were excluded.
Results: We identified 427 articles or abstracts to include for review. More than half were abstracts, and the majority were published after 2010. Reported TRALI definitions varied, but only 27.2% of studies reported any definition for TRALI. TRALI rates were reported using different denominators, such as per blood unit (54.1%), patient (34.4%), and transfusion episode (14.8%). Study populations and contexts were mostly general (75.6% and 80.3%, respectively). There was also variation in study design with most being observational (90.6%) and only 13.1% of all studies used modern donor restriction policies.
Discussion: There was substantial variation in reporting in studies on TRALI incidence. Meta-analysis of TRALI rates may be feasible in specific circumstances where reporting is clear. Future studies should clearly report key items, such as a TRALI definition.
Keywords: TRALI; blood transfusion; epidemiology; incidence; meta-analysis.
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