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SIR Model Explorer
CLABSI, CAUTI, MRSA Bacteremia LabID, CDI LabID
CDI LabID Event Risk Adjustment (CAHs)
The number of predicted CDI Lab ID 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 | -9.4938 | 0.1903 | <0.0001 |
| Outpatient CO prevalence rate1: >0 per 100 admissions | 0.4943 | 0.0883 | <0.0001 |
| Outpatient CO prevalence rate1: 0 per 100 admissions or no applicable locations | REFERENT | – | – |
| Inpatient CO prevalence rate2: ≥0.313 per 100 admissions | 0.4895 | 0.0909 | <0.0001 |
| Inpatient CO prevalence rate2: <0.313 per 100 admissions | REFERENT | – | – |
| CDI test type3: NAAT | 0.3893 | 0.0955 | <0.0001 |
| CDI test type3: EIA or Other | REFERENT | – | – |
| Average length of stay4: ≥2.6 days | 0.5290 | 0.1794 | 0.0032 |
| Average length of stay4: <2.6 days | REFERENT | – | – |
| Total number of beds4: <25 beds | 0.2403 | 0.0909 | 0.0082 |
| Total number of beds4: ≥25 beds | REFERENT | – | – |
Footnotes:
1 Outpatient community-onset (CO) prevalence rate combines CDI LabID data from all emergency departments (EDs) 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). 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.
2 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.
3 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:
- Nucleic acid amplification test (NAAT): This includes NAAT, Glutamate Dehydrogenase (GDH) plus NAAT (GDHNAAT), and GDH plus EIA for toxin, followed by NAAT for discrepant results (GDHEIA).
- Enzyme immunoassay (EIA) for toxin or Other: This includes EIA for toxin, GDH antigen plus EIA for toxin (GDH), NAAT plus EIA, if NAAT positive (2-step algorithm) (NAATEIA), and all other CDI test methods, including the selection of “Other”.
4 Average length of stay and total number of beds are taken from the Annual Hospital Survey [PDF – 1MB]. Average length of stay is calculated as: total # of annual patient days / total # of annual admissions.
