A total of 4549 patient visits were screened. After excluding patients not meeting the first two criteria (aged less than 75 at the time of visit or registered as resident of municipalities in other hospital districts, n=193) a total of 4356 patient visit codes were registered. For eligible patient visits a total of 2388 forms were returned filled with the nurse assessed CFS (55% of the forms). Nine forms were incorrectly filled and were excluded, leaving us with 2379 visits for analysis. Of the correctly filled forms, there were 1711/2379 visits with a CFS score of at least four (72%), and 668/2379 (28%) with CFS score of less than four. There were 1304 individual patients included in the study, with a total of 412/1711 (24%) revisits (Fig 1). Follow-up data from electronic health records were available for all included visits (n=1711).
Of the visits 664 (39%) were male patients and 1047 (61%) were female patients. Mean and median age was 85 years. Median CFS was 6. Mean ED LOS was 8.6 and median ED LOS was 6.2 hours. Median NEWS2-score was 1. There were a total of 412/1711 revisits during the 6-month study period. Of these revisits 351/1711 (20.5%) within 30 days and 48/1711 (2.8%) within 3 days. 96/1711 patients deceased within 30 days from their visit. 69/1711 (4.0%) patient visits were triaged as red and 356/1711 (20.8%) were triaged as yellow, data were missing for 8 visits. The remaining 1278/1711 (74.7%) were triaged as green.
The hospital admission rate was 64.4% (1103/1711) patients were admitted. Of those, 31 were admitted to an HDU facility, yet there were no ICU admissions.
Mortality
Patients with higher NEWS2 score had significantly increased 30-day mortality (p<0.001). In the ROC analysis AUC was 0.70 (95% CI 0.64-0.76) (Fig3a).
Mortality differed significantly between triage groups (p<0.001). In the red group, mortality was 23.2% (16/69); in the yellow group, 7.6% (27/356); and in the green group, 4.1% (52/1278). In the ROC analysis AUC was 0.62 (95% CI 0.56-0.68) (Fig 3b).
Hospital admission
Patients with higher NEWS2 scores were more frequently admitted (p<0.001). 42/43 (97.7%) patients with a NEWS2 score of at least 8 were admitted. 238/296 (80.4%) of patients with a NEWS2 score between 4 and 7 were admitted. Of those with a NEWS2 score of 3 or lower, 762/1308 (58.3%) were admitted. In the ROC analysis, AUC was 0.62 (95% CI 0.60-0.65)
There was a difference in hospital admission rates between triage groups (p<0.001). For patients in the red triage group admission rate was 94.2% (65/69); for the yellow group, admission rate was 68.5% (244/356); and for the green group 61.8% (790/1278). The AUC was 0.55 (95% CI 0.52-0.56) in the ROC analysis.
HDU admission
Of the 1102 admitted patients, 31 (2.8%) were admitted to an HDU facility. There were no ICU admissions from the ED in this study population. There was a significant increase in HDU admissions for patients with higher NEWS2 scores (p<0.001). The ROC analysis shows an AUC value of 0.72 (95% CI 0.61 – 0.83) (Fig 4a).
There was a significant increase in HDU admissions in the red and yellow triage categories (p<0.001). In the red group, 18/63 (28.6%) patients were admitted to HDU. In the yellow and green groups, the numbers of HDU admissions were 5/243 (2.1%) and 8/786 (1.0%), respectively. The ROC analysis shows AUC value of 0.80 (95% CI 0.70-0.90) (Fig 4b).
ED LOS
Mean LOS for the red group was 4.8 h (95% CI 4.2-5.5), for the yellow group 8.45 h (95% CI 7.8-9.1) and 8.8 h for the green group (95% CI 8.46-9.2). There was a significant difference in ED LOS between the red and the yellow patients (p<0.001) but not between the yellow and the green groups (p=0.59) (Table 1).
|
|
Mean Difference (h)
|
Std. Error
|
Sig.
|
95% CI
|
Lower
|
Upper
|
Triage group
|
|
Red
|
Yellow
|
-3.64*
|
0.852
|
<0.001
|
-5.63
|
-1.64
|
Red
|
Green
|
-4.02*
|
0.800
|
<0.001
|
-5.90
|
-2.14
|
Yellow
|
Green
|
-0.380
|
0.388
|
<0.001
|
-1.29
|
0.53
|
|
|
|
|
|
|
|
News2 risk group
|
|
|
|
|
|
Low
|
Moderate
|
0.07
|
0.564
|
0.993
|
-1.26
|
1.39
|
Low
|
High
|
1.19
|
0.549
|
0.077
|
-0.10
|
2.48
|
Moderate
|
High
|
1.13
|
0.748
|
0.289
|
-0.63
|
2.88
|
Table 1: Predictive values of triage score and NEWS2 for ED LOS
There were 1406 patient visits with a low NEWS2 score, mean LOS for this group was 8.67 h (95% CI 8.33-9.02). There were 148 patients with a moderate NEWS2 score, mean LOS of 8.61 h (95%CI 7.61-9.60) and 157 patients with a high NEWS2 score with a mean LOS of 7.48 h (95% CI 6.58-8.39). There were no significant differences between the groups (p=0.095) the exact figures are presented in Table 1.
Revisitation
There were 351 revisits within 30 days and 48 revisits within 3 days of the index visit. For all visits the AUC for 30- and 3-day revisit prediction with the NEWS2 score are 0.47 (95% CI 0.44-0.51) (p=0.13) and 0.48 (95% CI 0.40-0.56) (p=0.61) respectively. The AUC for 30- and 3-day revisit prediction with the triage score are 0.49 (95% CI 0.46-0.52) (p=0.57) and 0.48 (95% CI 0.40-0.56) (p=0.63) respectively.
In a post-hoc analysis for non-admitted patients, NEWS2 score did not predict 3-day revisitation (p=0.77, AUC 0.52 (95% CI 0.41-0.62)), nor did triage score (p=0.89, AUC 0.51 (95%CI 0.41-0.61)).
Strengths and limitations
The strength of our study is that we were able to include a relatively large study population. We had access to thorough documentation in the electronic patient records. We have systematically attempted to reduce bias by completing the STROBE checklist for cohort studies to assess bias (Appendix 2).
Our study was completed in a single centre, which might contribute to selection bias. The three-level triage tool that was used, has not been formally validated, thus our results might not be applicable to other ED’s that utilize different triage instruments. However, three-level triage instruments have been shown to be less sensitive compared to five-level instruments; therefore, any findings on a three-level instruments could be argued to be significant.
CFS was not assessed for almost a half of potentially eligible patients. Our hypothesis is that this happened especially due to crowding. This might contribute to selection bias, but the selection of patients was done independently from the researchers, which in turn might be a redeeming factor.