Which factors most influence demand for ambulances in South West England?

Abstract

Ambulance demand in South West England is increasing year-on-year, but the driving forces behind such increases are poorly understood. We developed a system dynamics model to simulate the factors that influence a call being made for an ambulance. We used data from the South West Ambulance Service NHS Foundation Trust (SWAST), the Office of National Statistics (ONS) and quantitative relationship data in both national and international literature to parameterise the model. We compared predicted ambulance demand over 12 months in the base case model with scenarios in which each influencing factor was removed in turn. The model predicts that the prevalence of regular falls among older people most influences the level of demand for ambulances. The model also predicts that the number of users of adult mental health services could be a significant contributor to ambulance demand. Additional focus on, and investment in, falls prevention strategies could help to significantly alleviate increasing levels of demand for ambulance services in South West England. Additionally, efforts to understand why those with mental health needs tend to use ambulances more than those without such needs could also be beneficial.