Emergency call triage priority predicts transport decisions and patient disposition in the London Ambulance Service

Background This study examines the link between emergency call triage priority and patient outcomes within the London Ambulance Service (LAS), with a focus on how triage decisions affect paramedic treatment and transport choices. As the world’s busiest ambulance service, LAS uses the Advanced Medical Priority Dispatch System under the Ambulance Response Programme to categorise incidents by urgency and allocate resources accordingly. Despite these structured frameworks, concerns remain about the accuracy of triage classifications and their impact on patient care, particularly regarding the risks of over- and under-triage. Methods Using 2023 data, this retrospective cohort study addresses three key questions: whether higher call priorities are linked to increased emergency transport rates; whether lower priorities correspond to more frequent community discharges; and whether paramedic medication administration alters these relationships. The analysis considers transport decisions, destination types (such as emergency departments, specialist units, or community care), and paramedic interventions as proxies for patient acuity. Results Results show that higher triage priorities are generally associated with greater likelihood of emergency transport and need for interventions, while lower priorities more often result in community discharge or referral to alternative care pathways. However, notable mismatches persist; some low-priority cases require urgent intervention, and some high-priority dispatches do not result in transport. Medication administration by paramedics emerged as a significant modifier, often indicating greater clinical severity and influencing transport decisions regardless of initial triage category. Conclusions The findings suggest that while current triage systems broadly align resources with patient needs, mismatches remain that can affect both patient safety and resource efficiency. These insights underscore the need for ongoing refinement of triage protocols and decision-support tools to optimise emergency medical service response and improve patient outcomes in complex urban settings like London.