Safety and accuracy of digitally supported primary and secondary urgent care telephone triage in England: an observational study using routine data.

backgroundEngland's urgent care telephone triage system comprises non-clinician-led primary triage (NHS111) assessment followed, for approximately 50% patients, by clinician-led secondary triage. Digital decision support is utilised by both. We explore the system's safety and accuracy relative to patients' use of emergency departments (EDs) and in-patient care in the subsequent 24 h.

methodsDescriptive analyses were used to investigate outcomes of 98,946 calls that underwent primary and secondary triage. We investigated sensitivity (safety) and specificity (efficiency/accuracy) in relation to subsequent ED attendance and in-patient hospital admission. Mixed effects regression models were used to explore potential under-estimation of clinical risk (under-triage).

resultsSensitivity was greater in primary triage, whilst specificity was greater in secondary triage. The positive predictive value for attending ED after being assigned a triage urgency level of within 2 h was 46.0% for secondary triage compared to 20.7% for primary triage; for inpatient admission it was 18.0% and 9.2% respectively. 1.5% (n = 1468) patients triaged to same-day or less urgent care at secondary triage were subsequently admitted for in-patient care. In relation to in-patient admission within 24 h, there were greater odds of potential under-triage for calls made between midnight and 6am, and for shorter duration calls, respectively OR = 1.71; CI:1.32-2.21 and OR: 1.66, CI: 1.30-2.11. The service provider (e.g., service provider 2, OR = 5.61; CI:3.36-9.36) and individual clinician (OR covering the 95% midrange = 16.15) conducting triage were the characteristics most greatly associated with this potential under-triage; p < 0.001 for all.

conclusionsClinician-led urgent care triage is more accurate in identifying the likelihood of a need for ED or in-patient care than non-clinician triage. Non-clinician primary triage is risk averse, reflected in its high sensitivity but low specificity. Service and clinician characteristics associated with potential under-triage need further investigation to inform ways of improving the safety and effectiveness of urgent care telephone triage. CLINICAL TRIAL NUMBER: Not applicable.