What Are They Worth? Six 30-Day Readmission Risk Scores for Medical Inpatients Externally Validated in a Swiss Cohort

BACKGROUND: Several clinical risk scores for unplanned 30-day readmission have been published, but there is a lack of external validation and head-to-head comparison. OBJECTIVE: Retrospective replication of six clinical risk scores (LACE, HOSPITAL, SEMI, RRS, PARA, Tsui et al.)f DESIGN: Models were fitted with the original intercept and beta coefficients as reported. Otherwise, a logistic model was refitted (SEMI and Tsui et al). We performed subgroup analyses on main admission specialty. This report adheres to the TRIPOD statement for reporting of prediction models. PARTICIPANTS: We used our prospective cohort of 15,639 medical patients from a Swiss tertiary care institution from 2016 through 2018. MAIN MEASURES: Thirty-day readmission rate and area under the curve (AUC 0.70 acceptable, > 0.80 excellent) CONCLUSIONS: Among several readmission risk scores, HOSPITAL, PARA, and the score from Tsui et al. showed the best predictive abilities and have high potential to improve patient care. Interventional research is now needed to understand the effects of these scores when used in clinical routine. KEY RESULTS: Among the six risk scores externally validated, calibration of the models was overall poor with overprediction of events, except for the HOSPITAL and the PARA scores. Discriminative abilities (AUC) were as follows: LACE 0.53 (95% CI 0.50–0.56), HOSPITAL 0.73 (95% CI 0.72–0.74), SEMI 0.47 (95% CI 0.46–0.49), RRS 0.64 (95% CI 0.62–0.66), PARA 0.72 (95% CI 0.72–0.74), and the score from Tsui et al. 0.73 (95% CI 0.72–0.75). Performance in subgroups did not differ from the overall performance, except for oncology patients in the PARA score (0.57, 95% CI 0.54–0.60), and nephrology patients in the SEMI index (0.25, 95% CI 0.18–0.31), respectively. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s11606-020-05638-z) contains supplementary material, which is available to authorized users.