Call Rates, Acuity and Outcomes Across Deprivation Quintiles: A Service Evaluation Using Yorkshire Ambulance Service Data with Embedded Patient and Public Involvement

Background/Objectives: Socioeconomic deprivation is consistently associated with worse health outcomes and unequal access to healthcare in England. Less is known about how deprivation relates to ambulance service use, call acuity and recorded outcomes. Yorkshire Ambulance Service (YAS) NHS Trust introduced NHS Pathways triage into its 999 service during 2025, replacing the Advanced Medical Priority Dispatch System and aligning 999 triage with the tool already in use in NHS 111, providing an opportunity to describe call patterns across the deprivation gradient under a standardised clinical assessment framework. This evaluation aimed to quantify and describe call rates, acuity and recorded outcomes across communities with varying levels of deprivation in Yorkshire, using routine NHS 111 and 999 call data, with embedded Patient and Public Involvement and Engagement (PPIE) to contextualise the findings. Methods: Population-based retrospective observational service evaluation using routine YAS operational data on calls assigned an ambulance acuity category (Categories 1–5) from 1 May 2024 to 28 February 2026 (22 months). Of 1,793,254 calls extracted, 1,748,057 (97.5%) could be linked to an Index of Multiple Deprivation (IMD) 2019 national quintile via incident postcode and formed the analytic set. Call rates per 1000 residents per year were calculated using published population estimates aggregated to quintile. Recontact within 24, 48 and 72 h was identified by linking calls sharing an NHS number recorded at the time of the call. Analysis was descriptive and was performed in Microsoft Excel and Python 3.11.15. Two PPIE workshops (Leeds, n = 12; Bradford, n = 7) were held in March 2026 with 19 participants, after the quantitative analysis was complete. Reporting follows the STROBE statement for cross-sectional studies and the GRIPP2 short-form checklist for the reporting of patient and public involvement. Results: The most deprived quintile (Q1) accounted for 688,950 calls (39.4%) and the least deprived (Q5) for 212,803 (12.2%), a crude count ratio of 3.2:1. Q1 contains 30.5% of the catchment population and Q5 15.4%; expressed per head of population, contact was 229.0 against 139.7 calls per 1000 residents per year, a rate ratio of 1.64:1. Callers in Q1 were younger than those in Q5 (median 56 years, IQR 35–76, against 78 years, IQR 59–86). Category 1 calls formed 12.9% of Q1 calls against 9.5% in Q5. Q1 had the highest Hear-and-Treat rate (14.8% vs. 12.1%) and the lowest conveyance rate (53.0% vs. 57.3%); among lower-acuity (Category 3–5) calls, conveyance was 27.9% in Q1 against 37.7% in Q5. Recontact within 72 h was highest in Q1 (15.0%) and lowest in Q4 (13.0%). Outcome distributions were broadly similar under AMPDS and NHS Pathways triage, but the two tools were in use in different periods. Conclusions: Ambulance service contact, call acuity and recorded outcomes were patterned across the deprivation gradient in this region. The magnitude of the difference in contact depended substantially on whether population denominators were used; a crude count ratio of 3.2:1 corresponded to a rate ratio of 1.64:1 per head of population. Callers in the most deprived quintile were 22 years younger at the median than those in the least deprived, and the absence of standardised and adjusted analyses is a major limitation. PPIE participants contributed contextual perspectives on primary care access and telephone triage, and co-produced seven priority research questions to guide future work.