Limitations
This study has some limitations. First, we may have missed important low
value practices that were not identified in the scoping review or
suggested by clinical experts. For example, no practices related to
surgical procedures were identified although significant variability in
orthopedic surgical intensity among trauma centres was reported in a
recent study.92 Second, by using a staged approach for
the inclusion of studies with the most rigorous evidence, we may have
missed some relevant studies. However, for practices with associated
systematic reviews or RCTs, we also included studies with a lower level
of evidence that were published more recently. Lastly, studies with a
high level of evidence were not found for all practices and most studies
were of low methodological quality or had a high risk of bias.