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2348 Modelling 111 demand for primary care services using discrete event simulation
  1. Richard Pilbery1,
  2. Madeleine Smith2,
  3. Jonathan Green3,
  4. Dan Chalk4,
  5. Colin O’Keeffe5
  1. 1Yorkshire Ambulance Service NHS Trust
  2. 2NHS Devon
  3. 3University of Plymouth
  4. 4University of Exeter
  5. 5University of Sheffield


Aims and Objectives Almost half of the 16,650,745 calls to NHS 111 each year are triaged to a primary care disposition. However, there is evidence that contact with a primary care service occurs in less than 50% of cases and triage time frames are frequently not met. This can result in increased utilisation of other healthcare services.

This study aimed to model in-silico the current healthcare system for patients triaged to a primary care disposition and determine the effect of reconfiguring the system to ensure a timely primary care service contact.

Method and Design Data from the Connected Yorkshire research database, consisting of all 111 calls made in 2021 by callers registered with Bradford or Airedale GP who were triaged to a primary care disposition, and subsequent healthcare system access in the 72 hours after the index 111 call, were used to develop a model and Discrete Event Simulation in Python, using the SimPy package.

We simulated 100 runs of one year of 111 calls and calculated the mean difference and 95% confidence intervals in primary care contacts, 999 calls and avoidable ED attendances.

Results and Conclusion The simulation of the current system estimated that there would be 39,485 (95%CI 39,437—39,534) primary care contacts, 2,059 (95%CI 2,050—2,068) 999 calls and 1,137 (95%CI 1,129—1,145) avoidable ED attendances. Modifying the model to ensure a timely primary care response resulted in a mean increase in primary care contacts of 37,755 (95%CI 37,675—37,835), a mean reduction in 999 calls of 443 (95%CI 430–456) and a mean reduction in avoidable ED attendance of 39 (95%CI 29–49).

The model suggests that timely contact with a primary care service reduces 999 calls, but has minimal impact on avoidable ED attendance, and is likely impractical given that primary care service capacity would need to double.

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