Table 3.
Comparison of eCART, NEWS and AAMa scores using validation data.
| Performance metric | eCART | NEWS | AAM |
|---|---|---|---|
| Training cutoffb | 50 | 8 | 7.5 |
| Number of episodesc | 168,811 | ||
| Number of alerts | 15,274 | 13,129 | 15,288 |
| % alerts with events (PPVd) within: | |||
| 12 h | 7.8% | 7.6% | 8.4% |
| 24 h | 9.7% | 9.8% | 10.5% |
| Entire hospitalization episode | 14.4% | 15.2% | 16.2% |
| W:De at: | |||
| 12 h | 12.7 | 13.1 | 11.9 |
| 24 h | 10.3 | 10.2 | 9.5 |
| Entire hospitalization episode | 6.9 | 6.6 | 6.2 |
| Number not alerted | 153,537 | 155,682 | 153,523 |
| % of no alerts with no event (NPV) | 98.2% | 98.0% | 98.3% |
| Number of events | 5047 | ||
| Sensitivity in prior: | |||
| 12 h | 23.7% | 19.9% | 25.4% |
| 24 h | 29.4% | 25.6% | 31.9% |
| Entire hospitalization episode | 43.7% | 39.5% | 48.9% |
| Number with no event | 163,764 | 163,764 | 163,764 |
| Specificity | 92.0% | 93.2% | 92.2% |
See text for details on the 3 scores (NEWS, National Early Warning Score; eCART, electronic Cardiac Arrest Triage; AAM (Advanced Alert Monitoring). The table indicates specific metrics (left column) when the three scores were applied to hourly retrospective data.
Each respective score’s training cutoff was determined so that there would be no more than 1 alert per day in a hospital with an average daily census of ~35 patients. An alert was triggered if the score was greater than the training cutoff.
In those instances where the patient was transferred to intensive care more than once, we split the original episode into separate episodes (each time a patient returned to the ward, a new episode began) to fully evaluate episodes that had multiple outcomes.
PPV, positive predictive value; NPV, negative predictive value.
W:D, work-up to detection ratio (also known as number needed to evaluate).