Agreement and predictive value of the Rockwood Clinical Frailty Scale at emergency department triage

Abstract

Aim: To determine the agreement and predictive value of emergency department (ED) triage nurse scoring of frailty using the Rockwood Clinical Frailty Scale (CFS) when compared with inpatient medical assessment using the same scale.

Methods: Prospective, dual-centre UK-based study over a 1-year period (1 April 2017 to 31 March 2018) of CFS recorded digitally at nursing triage on ED arrival and on hospital admission by a medical doctor. Inclusion criteria were emergency medical admission in those aged ≥65 staying at least one night in hospital with a CFS completed in both ED and at hospital admission. Agreement between ED triage nurse and inpatient hospital physician was assessed using a weighted Kappa statistic and Spearman's correlation coefficient. The ability of the ED to diagnose frailty (defined by a CFS ≥5) was assessed using sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and receiver operating characteristic (ROC) curves. At both time points the ability of the CFS to predict inpatient mortality was also assessed.

Results: From 29 211 admissions aged ≥65 who stayed at least one night in hospital, 12 385 (42.3%) were referred from the ED. Of the ED referrals, 8568 cases (69.2%) were included with paired CFS performed. Median age was 84 (IQR 77 to 89) with an inpatient mortality of 6%. Median CFS in ED was 4 (3 to 5) and on hospital admission 5 (4 to 6). Agreement between the ED CFS and admission CFS was weak (Kappa 0.21, 95% CI 0.19 to 0.22, r_s 0.366). The area under the ROC curve (AUC) was 0.67 (95% CI 0.66 to 0.68) for the ED CFS ability to predict an admission CFS ≥5. To predict inpatient mortality the ED CFS AUC was 0.56 (0.53 to 0.59) and admission CFS AUC 0.70 (0.68 to 0.73).

Conclusion: Agreement between ED CFS and inpatient CFS was found to be weak. In addition the ability of ED CFS to predict clinically important outcomes was limited. NPV and PPV for ED CFS cut-off value of ≥5 were found to be low. Further work is required on the feasibility, clinical impact and appropriate tools for screening of frailty in EDs.

Keywords: emergency department; frailty; triage.