Background

The growing number of older adults presenting to the Emergency Department (ED) challenges traditional models of acute care, which are often poorly aligned with the complex and heterogeneous needs of this population. Frailty, characterized by decreased physiological reserve and increased vulnerability to stressors, has emerged as a key determinant of adverse outcomes in older patients. However, frailty is not systematically integrated into ED assessment and decision-making, which could be explained by persisting knowledge gaps. Comparison among various frailty assessment instruments in ED settings, has demonstrated good prognostic ability regarding adverse outcomes. Their ease of use in this time- and resource-pressured environment has been evaluated, in which the globally used assessment tool CFS was gauged as usable in the ED. Focus on specific patient groups and research personnel conducting the CFS assessments have limited the generalizability of previous research, resulting in lacking evidence of the instrument’s applicability and usability in actual emergency medicine.

Aim

Since uncertainty remains regarding the instrument’s usefulness in EDs, this thesis aims to answer (1) whether frailty assessment performed by regular ED staff retains prognostic validity in real-world conditions, (2) whether frailty adds relevant predictive value beyond established triage systems, (3) how feasible and acceptable frailty assessment with CFS is within time-pressured ED workflows, and (4) whether frailty-informed routines, assessed with CFS early during the ED visit, can improve operational performance.

Method

This thesis consists of Studies I-IV with observational, both prospective and before-and-after, as well as mixed-method designs. Study I was a prospective observational multicentre study conducted in three EDs in the council of Östergötland, Sweden. Study II was a secondary analysis of Study I. Study III, a mixed-method study, was carried out in the same three EDs as Study I. Study IV was a single-centre observational before-and-after study conducted in the Emergency department of University Hospital of Linköping, Sweden.

Study I investigated the prognostic ability of CFS assessments made by regular ED staff during real-life clinical work. All assessed patients aged 65 years and above were eligible for inclusion. The primary outcome was mortality at 30 days, and secondary outcomes were mortality at 7 and 90 days, admission rate, ED and hospital length of stay (LOS). Outcomes were compared between patients living with frailty (CFS>4) and robust patients (CFS<5). Confounders were adjusted for using logistic regression

Study II investigated the prognostic performance of CFS alone or in connection with the existing warning scores: national early warning score (NEWS), triage early warning score (TEWS) or the rapid emergency triage and treatment system (RETTS) triage tool. The prognostic ability was analysed using logistic regression and the primary and secondary outcomes were the same as Study I and are reported as area under the receiver operating curve (AuROC) scores with 95% confidence intervals (CIs).

Study III was a mixed-method study that examined the feasibility and acceptability of CFS in ED by collecting completion rate of assessed patients and by analysing staff experience gathered via an electronic questionnaire. Open-ended questions in the questionnaire rendered free-text comments which were analysed using qualitative content analysis. Quantitative data were analysed to identify patient-related and organisational factors and reported as descriptive data.

Study IV was a before-and-after observational study of the effects of a frailty-informed routine where patients with CFS >4 were recommended to be prioritised for physician assessment among patients with the same acuity after triage. The primary outcome was ED LOS, and secondary outcomes were time to physician and admission rate. Outcomes were compared between a pre-implementation group (control) and a post- implementation group (intervention).

Results

Mortality was significantly higher in patients with CFS >4 at 30 days (7.9% vs 0.9%) with an adjusted odds ratio of 6.0 (95% CI 3.0-12.2, p < 0.001) in the total of 1840 ED visits that were included in the analysis. There were significant differences in mortality at 7 and 90 days, where mortality was higher for patients living with frailty. The differences remained even after adjusting for confounders. Patients living with frailty also had higher admission rates, longer ED LOS, and longer in-hospital LOS, compared to the robust patients.

A total of 1832 patients were included in Study II, where the association between mortality at 30 days and CFS >4 showed a significant association with an odds ratio of 6.0 (CI 95% 3-12, p < 0.01). Prognostication models demonstrated better prognostic ability in those models with CFS compared to those without and were overall similar in AuROC-values ranging from 0.82-0.83 (95% CI 0.77-0.88, p < 0.05).

Feasibility investigation showed a completion rate of 47% in 4235 ED visits. Assessments were made more frequently if the patients were aged >80 years, arrived by ambulance or during the forenoon. The questionnaire revealed that CFS was thought to be a relevant tool but high workload, unclear purpose for use and critical illness, were barriers for usability in the ED.

A total of 542 ED visits were analysed in the before-and-after study with 248 patients in the pre‐implementation and 294 in the post‐implementation group). Post-implementation showed a reduction in Time to physician from 44 min (IQR 20, 94) to 31 min (IQR 15, 65) (p < 0.001). ED LOS was shortened from 352 (IQR 266, 515) to 319 (IQR 240, 458) minutes (p = 0.014). There was no change in admission rate at 59% versus 60% (p = 0.4).

Conclusion

This thesis confirms the robustness and validity of CFS as a prognostic tool outside of controlled research settings and demonstrates that addition of frailty to conventional triage tools captures risk and vulnerability not reflected in vital signs and chief complaint alone. The CFS provides a more accurate risk prognosis which is valuable for establishing realistic goals-of-care and individualising medical planning. A clear ED routine including early frailty identification and connected actions could improve ED flow and decrease avoidable risks associated with prolonged ED stays, which in turn would benefit both the patients and the ED organisation as a whole.