Results
During the study period (2 years), 1916 discharges were recorded for the SIU-SOM Hospitalist service. The analysis includes data for the 1781 discharges for 1410 individual patients that met inclusion criteria (Figure 1). Of these discharges, 456 (26%) were readmitted to the same hospital within 30 days. The overall study population was 47% female, had an average age of 63 years, and spent an average of 7.9 days in the hospital.
The patients readmitted, compared to the patients who were not readmitted, were more frequently readmitted to the hospital in the last year, evaluated in the emergency department in the last 6 months, had higher HOSPITAL scores, and had higher LACE index values. Those differences were statistically significant (Table 3).
One or more unstable vital signs at the time of discharge were seen in 13% of the study population. The frequency of discharges with any vital sign instability was slightly higher (15% vs. 12%, p = 0.084) in the group that was readmitted to the same hospital within 30 days, but this did not reach statistical significance (Table 3, Figure 2). The presence of only one unstable vital sign was present in a higher proportion of the study population that was readmitted to the hospital within 30 days of discharge (14.5% vs. 10.6%, p = 0.024). Two unstable vital signs were more common in the group not readmitted within 30 days of discharge (1.4% vs. 0.06%, p = 0.196), but this did not reach statistical significance. No discharges had 3 or more unstable vital signs.
Receiver operating characteristic (ROC) comparisons of the HOSPITAL score (C statistic of 0.67, 95% CI 0.65 – 0.71), LACE index (C statistic of 0.61, 95% CI 0.58 - 0.64), and vital sign instability (C statistic of 0.52, 95% CI 0.49 – 0.55) are shown in Figure 3. The area under the curve (AUC) is statistically significant for the HOSPITAL Score (p < 0.001) and LACE Index (p < 0.001), but not for vital sign instability (p = 0.318).