Letter to the editor: association between delays to patient admission from the emergency department and all-cause 30-day mortality

We read with interest the recently published article by Jones et al.1 This paper provides important data to inform the debate around the current 4-hour target and the currently considered changes laid out in a recent government white paper.2 The use of national admissions data linked with robust mortality information is a considerable undertaking and the authors should be congratulated on their methods. This study potentially represents the best information available to make the judgements required in planning for the future of emergency care. Because of the significant implications of this work, we would like to highlight some important considerations for its interpretation. In particular, while the authors have presented convincing data to demonstrate an association between length of ED stay and 28-day mortality, it is imperative to understand that this does not necessarily imply that long ED stays cause the increased mortality rate. ©