Background: Hospital readmissions are common, detrimental for patients and associated with significant costs for the healthcare system. The aim of this study was to evaluate simplified HOSPITAL score (Aubert et al, 2017) in 30-day non-elective readmission prediction at a Brazilian tertiary care teaching public hospital in Southern Brazil.

Methods: Retrospective cohort study including all hospital discharges from the Internal Medicine Service at the study facility from September to November 2017. To analyze the simplified HOSPITAL score (0-12 points), the following variables were assessed: hemoglobin level at discharge < 12 g/L (1 point), cancer diagnosis (2 points), sodium level at discharge < 135 mmol/L (1 point), index type of admission: non-elective (1 point), hospital admissions during the previous 12 months [0-1 (0 point), 2-5 (2 points), > 5 (5 points)] and length of stay ≥ 5 days (2 points). The area under the ROC curve (AUC) was calculated to evaluate the ability of the score in predicting readmissions at the same hospital and other two electronic medical records connected hospitals. The best cutoff point was identified through the Youden index. Poisson regression with robust variance was used to identify independent predictors of hospital mortality among score components. A P < 0.05 was considered statistically significant.

Results: A total of 1,038 hospital discharges were included [median age 65.9 (IQR: 51.9-75.9) years, 52.1% female]. Median simplified HOSPITAL score was 4 (IQR: 3-5) points. Cancer diagnosis was described in 201 (19.4%) index admissions [median Charlson score 2 (1-3) points]. Low hemoglobin and sodium level at discharge were observed in 627 (60.4%) and 89 (8.7%) of index hospitalizations, respectively. Most of the index admissions were non non-elective (1,026, 98.8%) and a length of stay ≥ 5 days was observed in 923 (88.9%) [median 10 (IQR: 6-17) days]. Rate of ≥ 2 admissions during the previous 12 months was 15.5%. Overall 30-day non-elective readmission rate was 14.5% (95%CI: 12.4-16.6%). AUC was 0.68 (95%CI: 0.63-0.73; P < 0.001). Hospital discharges with ≥ 6 points had a readmission rate of 30.8% (0-5 points: 9.7%; P < 0.001). Three readmission risk categories were identified: low (0-2 points: 4.3%), moderate (3-5 points: 10.4%) and high (≥ 6 points: 30.8%). Only cancer diagnosis (RR 2.48, 95%CI: 1.82-3.37), sodium level at discharge < 135 mmol/L (RR 1.57, 95%CI: 1.06-2.33) and ≥ 2 hospital admissions during the previous 12 months (RR 1.53, 95%CI: 1.09-2.14) were independent predictors of readmission.

Conclusions: Simplified HOSPITAL score had an AUC of 0.68, very similar to your original study (AUC 0.69), identifying a high readmission risk group of patients (score ≥ 6 points, 30.8%). Identification of this high risk group before hospital discharge could allow prioritize efforts to make a better transition of care.