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Risk Adjustment Factors Included in the SIR
MRSA Bacteremia LabID
MRSA Bacteremia Risk Adjustment (IRFs)
The number of predicted MRSA bacteremia 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 MRSA bacteremia 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).
| Parameter | Parameter Estimate | Standard Error | P-value |
| Intercept | -12.4554 | 0.3957 | <0.0001 |
| IRF Unit1 | 0.9396 | 0.2480 | 0.0002 |
| Free-standing Rehabilitation Hospital1 | REFERENT | – | – |
| Average length of stay2: ≥12.1 days | 0.8929 | 0.3561 | 0.0122 |
| Average length of stay2: <12.1 days | REFERENT | – | – |
Footnotes:
1Please refer to NHSN’s Guide to the SIR (2022 baseline) for the definition of IRFs used for NHSN purposes.
2 Average length of stay is calculated as: total # of annual patient days / total # of annual admissions, as reported on the Annual IRF Survey.
