Table 1.
Patients and Hospitalization Characteristics for Derivation, Validation, and Full Cohort for the Acute Care SMR-30 Model
| Total cohort FY 2017–2019 |
Derivation cohort FY 2017–2018 |
Validation cohort FY 2019 |
|
|---|---|---|---|
| Hospitalizations, N | 1,143,351 | 769,924 | 373,727 |
| Unique patients, N | 702,866 | 512,868 | 198,998 |
| Male, % of hospitalizations | 94.4% | 94.5% | 94.2% |
| Self-reported race, % of hospitalizations | |||
| White | 70.8% | 71.1% | 70.1% |
| Black or African American | 21.5% | 21.3% | 22.1% |
| Other, unknown, or not reported | 7.7% | 7.6% | 7.8% |
| Age, median (IQR) | 68 (61,74) | 68 (61,74) | 68 (61,75) |
| Number of comorbid conditions, median (IQR) | 3 (2,5) | 2 (2,4) | 3 (2,5) |
| Select comorbid conditions, % of hospitalizations | |||
| Congestive heart failure | 12.7% | 12.2% | 13.7% |
| Chronic pulmonary disease | 23.9% | 23.6% | 24.7% |
| Liver disease | 7.7% | 7.6% | 8.0% |
| Metastatic cancer | 2.4% | 2.4% | 2.6% |
| Immunosuppressed status (indicator in SMR models) | 22.5% | 22.2% | 23.1% |
| Admission Source | |||
| Other hospital (VA or non-VA) | 2.4% | 2.3% | 2.5% |
| Nursing home (VA or non-VA) | 1.9% | 1.8% | 2.0% |
| Operating Room | 15.1% | 15.3% | 14.7% |
| Other (Emergency Department, Direct Admission) | 80.6% | 80.6% | 80.8% |
| Admitting diagnosis category*, % of hospitalizations | |||
| Musculoskeletal (besides hip fracture) | 7.5% | 7.5% | 7.5% |
| Congestive heart failure | 5.7% | 5.7% | 5.9% |
| Infections (besides sepsis or pneumonia) | 5.6% | 5.7% | 5.3% |
| Neurologic diseases | 5.2% | 5.2% | 5.1% |
| Sepsis | 4.5% | 4.2% | 5.1% |
| Substance-related disorders | 4.3% | 4.2% | 4.4% |
| Chronic obstructive pulmonary disease | 4.0% | 4.1% | 3.9% |
| Cardiac dysrhythmias | 3.7% | 3.6% | 3.7% |
| Other gastrointestinal disease | 3.7% | 3.8% | 3.7% |
| Complications of surgical/medical care | 3.5% | 3.5% | 3.6% |
| All other diagnosis categories | 52.3% | 52.5% | 51.8% |
| DRG grouping, % of hospitalizations | |||
| Medical | 77.4% | 76.8% | 78.5% |
| Surgical | 21.6% | 21.7% | 21.3% |
| Major surgical procedure within 24 h, % | 15.5% | 15.7% | 15.1% |
| Length of hospitalization in days, median (IQR) | 2 (1,4) | 3 (1,4) | 2 (1,4) |
| ICU admission, % of hospitalizations | |||
| Directly admitted directly to ICU | 14.4% | 14.4% | 14.2% |
| Ever admitted to ICU | 18.0% | 18.1% | 17.8% |
| Mortality, % of hospitalizations | |||
| In-hospital | 1.8% | 1.7% | 1.8% |
| 30-day | 4.3% | 4.3% | 4.3% |
*Hospitalizations were each assigned to one of 51 mutually exclusive diagnosis categories based on their admitting diagnosis. These diagnosis categories each include one or more clinical classification software8(CCS) diagnosis categories. The consolidation of CCS categories into admission diagnosis categories was informed by clinical rationale, as well as by the observed mortality rates for CCS categories. For example, the musculoskeletal category is relatively large because it combines several low-risk CCS categories including diagnoses related to back, knee, facial, and extremity injury or illness, but hip fracture is kept as a separate category due to its higher associated mortality