Trial outcomes should be relevant to all stakeholders, and allow assessment of interventions’ efficacy and safety at appropriate timeframes. There is no consensus regarding outcome measures in the growing field of pre-hospital trauma transfusion research. Harmonization of future clinical outcome reporting is key to facilitate inter-study comparisons and generate cohesive, robust evidence to guide practice.
To evaluate outcome measures reported in pre-hospital trauma transfusion trials.
Data Sources, Eligibility Criteria, Participants and Interventions
We conducted a scoping systematic review to identify the type, number and definitions of outcomes reported in randomised controlled trials, prospective and retrospective observational cohort studies investigating pre-hospital blood component transfusion in adult and paediatric patients with traumatic haemorrhage. Electronic database searching of PubMed, Embase, Web of Science, Cochrane, OVID, clinical trials.gov, and the Transfusion Evidence Library was completed in accordance with PRISMA guidelines.
Study Appraisal and Synthesis Methods
Two review authors independently extracted outcome data. Unique lists of salutogenic (patient-reported health and wellbeing outcomes) and non-salutogenic focused outcomes were established.
3,471 records were identified. 34 studies fulfilled inclusion criteria: four military (n = 1,566 patients) and 30 civilian (n = 14,398 patients), all between 2000 and 2020. 212 individual non-patient-reported outcomes were identified, which collapsed into 20 outcome domains with varied definitions and timings. All primary outcomes measured effectiveness, rather than safety or complications. 69% reported mortality, with 11 different definitions. No salutogenic outcomes were reported.
The review is limited by a lack of high-grade prospective comparative trials with clear predefined primary outcomes
Conclusion and Implications of Key Findings
There is heterogeneity in outcome reporting and definitions, an absence of patient-reported outcome, and an emphasis on clinical effectiveness rather than safety or adverse events in pre-hospital trauma transfusion trials. We recommend stakeholder consultation and a Delphi process to develop a clearly defined minimum core outcome set for pre-hospital trauma transfusion trials.
Systematic Review Registration Number
This review was prospectively registered with PROSPERO (CRD42019131406).
Level of Evidence:
Scoping Systematic Review