Table 2:
Changes in model performance with addition of different predictors (validation dataset)
| C-statistics (AUROC) with
95% confidence intervals |
Change in AUROC over reference model |
Nagelkerke R2 | ||||
|---|---|---|---|---|---|---|
| Logistic model covariates |
30-day Readmission |
Composite outcome (30-day Readmission OR death) |
30-day Readmission |
Composite outcome (30-day Readmission OR death) |
30-day Readmission |
Composite outcome (30-day Readmission OR death) |
| Age, sex, LOS1, admission category2 (Reference) | 0.637 [0.634-0.640] | 0.675 [0.672-0.677] | Reference | Reference | 0.047 | 0.081 |
| Reference + Diagnosis groupings 3 | 0.651 [0.648-0.654] | 0.687 [0.685-0.690] | 0.014 | 0.012 | 0.057 | 0.095 |
| Reference + LAPS24 | 0.661 [0.658-0.664] | 0.704 [0.701-0.706] | 0.024 | 0.029 | 0.061 | 0.111 |
| Reference + RxDxCG5 | 0.683 [0.681-0.686] | 0.709 [0.707-0.712] | 0.046 | 0.034 | 0.079 | 0.113 |
| Reference + Drug subgroups6 | 0.684 [0.681-0.687] | 0.709 [0.707-0.711] | 0.047 | 0.034 | 0.085 | 0.118 |
| Reference + COPS27 | 0.704 [0.702-0.707] | 0.730 [0.728-0.733] | 0.067 | 0.055 | 0.102 | 0.141 |
| Reference + LAPS2 + COPS2 + RxDxCG | 0.712 [0.710-0.715] | 0.744 [0.741-0.746] | 0.075 | 0.069 | 0.112 | 0.162 |
| Reference + LAPS2 + COPS2 + RxDxCG + Diagnosis groupings + Drug subgroups | 0.716 [0.713-0.718] | 0.748 [0.746-0.750] | 0.079 | 0.073 | 0.120 | 0.172 |
LOS: Length of stay in hours
Admission category: A categorical variable differentiating admission through emergency department (ED) and admission to a medical or surgical service- the four categories were therefore: ED surgical, non-ED surgical, ED medical, non-ED medical
Diagnosis groupings: 42 groupings of diagnosis e.g. cancers, trauma, endocrine, neurological, nutritional etc.
LAPS2: Laboratory Acute Physiology Score, version 2; an acute physiology-based score that includes lactate, vital signs, neurological status checks, and pulse oximetry. Increasing degrees of physiologic derangement are reflected in a higher LAPS2, which is a continuous variable that can range between a minimum of zero and a theoretical maximum of 414, although < 0.05% of patients in our cohort had a LAPS2 exceeding 227 and none had a LAPS2 > 282. Increasing values of LAPS2 are associated with increasing mortality 4
RxDxCG: Proprietary risk adjustment system by Verisk
Drug subgroups: 21 drug classes as assigned by Verisk software
COPS2: COmorbidity Point Score, version 2; a longitudinal, diagnosis-based score assigned monthly that employs all diagnoses incurred by a patient in the preceding 12 months that results in a single continuous variable that can range between a minimum of zero and a theoretical maximum of 1,014, although < 0.05% of patients in our cohort had a COPS2 exceeding 241 and none had a COPS2 > 306 (Escobar et al, 2015). Increasing values of the COPS2 are associated with increasing mortality 4