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SIR Model Explorer
CLABSI, CAUTI, MRSA Bacteremia LabID, CDI LabID
CDI LabID Event Risk Adjustment (ACHs)
The number of predicted CDI LabID events under the 2022 baseline is calculated using a negative binomial regression model and is risk adjusted based on the following variables found to be statistically significant predictors of CDI incidence. Information about the statistical properties of NHSN risk adjustment models, including how the number of predicted events is calculated, is available in NHSN’s Guide to the SIR (2022 baseline) [PDF – 1MB].
| Parameter | Parameter Estimate | Standard Error | P-value |
| Intercept | -10.1452 | 0.1063 | <0.0001 |
| Inpatient CO prevalence rate1: ≥0.461 per 100 admissions | 0.7994 | 0.0371 | <0.0001 |
| Inpatient CO prevalence rate1: 0.301-0.460 per 100 admissions | 0.6666 | 0.0349 | <0.0001 |
| Inpatient CO prevalence rate1: 0.213-0.300 per 100 admissions | 0.5137 | 0.0346 | <0.0001 |
| Inpatient CO prevalence rate1: 0.152-0.212 per 100 admissions | 0.4296 | 0.0341 | <0.0001 |
| Inpatient CO prevalence rate1: 0.104-0.151 per 100 admissions | 0.3211 | 0.0340 | <0.0001 |
| Inpatient CO prevalence rate1: 0.064-0.103 per 100 admissions | 0.2443 | 0.0339 | <0.0001 |
| Inpatient CO prevalence rate1: 0-0.063 per 100 admissions | 0.1118 | 0.0338 | 0.0010 |
| Inpatient CO prevalence rate1: 0 per 100 admissions | REFERENT | – | – |
| CDI test type2: EIA or Other | 0.0960 | 0.0260 | 0.0002 |
| CDI test type2: NAAT | 0.2868 | 0.0193 | <0.0001 |
| CDI test type2: NAATEIA | REFERENT | – | – |
| Outpatient CO prevalence rate3: ≥0.048 per 100 admissions | 0.2914 | 0.0224 | <0.0001 |
| Outpatient CO prevalence rate3: 0.025-0.047 per 100 admissions | 0.2240 | 0.0215 | <0.0001 |
| Outpatient CO prevalence3: 0.012-0.024 per 100 admissions | 0.1064 | 0.0221 | <0.0001 |
| Outpatient CO prevalence rate3: <0.012 per 100 admissions or no applicable locations | REFERENT | – | – |
| Facility type (based on NHSN enrollment):
Oncology Hospital (HOSP-ONC) |
1.6881 | 0.1326 | <0.0001 |
| Facility type (based on NHSN enrollment):
General Acute Care Hospital (HOSP-GEN) Children’s Hospital (HOSP-CHLD) Military Hospital (HOSP-MIL) |
0.6225 | 0.0977 | <0.0001 |
| Facility type (based on NHSN enrollment):
Orthopedic Hospital (HOSP-ORTHO) Surgical Hospital (HOSP-SURG) Women’s Hospital (HOSP-WOM) Women’s and Children’s Hospital (HOSP-WOMCHILD) |
REFERENT | – | – |
| Number of ICU beds4: ≥80 | 0.5765 | 0.0526 | <0.0001 |
| Number of ICU beds4: 4679 | 0.3876 | 0.0525 | <0.0001 |
| Number of ICU beds4: 545 | 0.3330 | 0.0499 | <0.0001 |
| Number of ICU beds4: 04 | REFERENT | – | – |
| Medical school affiliation4: Major/Graduate/Non-teaching | 0.1677 | 0.0224 | <0.0001 |
| Medical school affiliation4: Undergraduate | REFERENT | – | – |
| Average length of stay4: ≥5.4 days | 0.0895 | 0.0173 | <0.0001 |
| Average length of stay4: <5.4 days | REFERENT | – | – |
1 Inpatient community-onset (CO) prevalence is calculated as the # of inpatient CO CDI de-duplicated events, divided by total admissions * 100 (i.e., cdif_admPrevCOCount_bs3 / numadms * 100). The prevalence rate for the entire quarter is used in risk adjustment.
2 CDI test method is reported on the FacWideIN MDRO/CDI denominator form on the 3rd month of each quarter. CDI test type is categorized as:
- Enzyme immunoassay (EIA) for toxin or Other: This includes EIA for toxin, glutamate dehydrogenase (GDH) antigen plus EIA for toxin (GDH), toxigenic culture (ToxiCul), cell cytotoxicity neutralization assay (Cyto), and the selection of ‘Other’ (OTH).
- Nucleic acid amplification test (NAAT): This includes NAAT, GDH plus NAAT (GDHNAAT), and GDH plus EIA for toxin, followed by NAAT for discrepant results (GDHEIA).
- NAAT plus EIA (NAATEIA): This includes NAAT plus EIA, if NAAT positive (2-step algorithm).
3 Outpatient community-onset (CO) prevalence rate combines CDI data from all EDs and/or 24-hour observation units into a single, de-duplicated prevalence rate. This rate is calculated as the # of unique community-onset CDI events that occurred in an ED or 24-hour observation unit, divided by total encounters * 100 (i.e., cdif_EDOBSprevCount / numTotencounters * 100). The prevalence rate for the entire quarter is used in risk adjustment. NOTE: If the facility does not have an ED or 24-hour observation location that meets the NHSN location definition and thus are not reporting CDI event data from these locations, the number of predicted events will be risk adjusted using the referent level of this variable.
4 Number of ICU beds and medical school affiliation are reported on the Annual Hospital Survey [PDF – 1MB]. Average length of stay is calculated as: total # of annual patient days / total # of annual admissions, as reported on the Annual Hospital Survey [PDF – 1MB].
