Table 2.
Most Important Variables by Permutation Importance in Random Forest Model Compared to Variables in Existing Sepsis Clinical Decision Rules
| Variables of Importance* | Random Forest | MEDS | m-REMS | CURB-65 |
|---|---|---|---|---|
| Oxygen saturation† | RF | MEDS‡ | mREMS‡ | CURB-65‡ |
| Respiratory rate† | RF | MEDS‡ | mREMS‡ | CURB-65‡ |
| Blood pressure† | RF | MEDS‡ | mREMS‡ | CURB-65‡ |
| BUN | RF | CURB-65‡ | ||
| Albumin | RF | |||
| Intubation† | RF | |||
| Procedures (in ED) | RF | |||
| Need for vasopressors | RF | |||
| Age | RF | MEDS‡ | mREMS‡ | CURB-65‡ |
| RN, resp care | RF | |||
| RDW | RF | |||
| Potassium | RF | |||
| AST | RF | |||
| Heart rate† | RF | mREMS‡ | ||
| Acuity level (triage) | RF | |||
| ED impression (Dx) | RF | |||
| CO2 (Lab) | RF | |||
| ECG performed | RF | |||
| Beta-blocker (Home Med) | RF | |||
| Cardiac dysrhythmia (PMHx) | RF |
All four scoring systems presupposed infectious illness and included additional variables not listed.
CURB-65 = Confusion, Urea nitrogen, Respiratory rate, Blood pressure, ≥65 years; MEDS = Mortality in ED Sepsis; mREMS = modified Rapid Emergency Medicine Score.
*
Based on permutation importance.
†
Combination of variable in all dimensions (e.g., RSI drugs administered and intubation procedure done).
‡
Score includes data element in at least one dimension (e.g., O2 sat) but may not have other dimensions (e.g. max, min).