An official website of the United States government
Risk Adjustment Factors Included in the SIR
Surgical Site Infections
Abdominal Hysterectomy (HYST) Procedures, Complex 30-Day Model
The number of predicted SSI events under the 2022 baseline is calculated using a logistic regression model and is risk adjusted based on the following variables found to be statistically significant predictors of SSIs. 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 | -6.4524 | 0.1514 | <.0001 |
| Procedure duration: 80-136 (Min) | 0.4701 | 0.0755 | <.0001 |
| Procedure duration: 137-188 (Min) | 0.7385 | 0.0804 | <.0001 |
| Procedure duration: ≥189 (Min) | 0.9316 | 0.0794 | <.0001 |
| Procedure duration: ≤79 (Min) | REFERENT | – | – |
| BMI: ≥30 | 0.2188 | 0.0476 | <.0001 |
| BMI: <30 | REFERENT | – | – |
| Patient’s age: 18-47 years | 0.6110 | 0.0569 | <.0001 |
| Patient’s age: 48-55 years | 0.3018 | 0.0690 | <.0001 |
| Patient’s age: 56-109 years | REFERENT | – | – |
| ASA score: 2 | 0.3276 | 0.1300 | 0.0118 |
| ASA score: 3/4/5 | 0.5465 | 0.1338 | <.0001 |
| ASA score: 1 | REFERENT | – | – |
| Scope: No | 0.1667 | 0.0449 | 0.0002 |
| Scope: Yes | REFERENT | – | – |
| Medical School Affiliation1: Major | 0.0934 | 0.0473 | 0.0483 |
| Medical School Affiliation1: Graduate/Undergraduate/None | REFERENT | – | – |
| Oncology Hospital2: Yes | 0.5740 | 0.1552 | 0.0002 |
| Oncology Hospital2: No | REFERENT | – | – |
| Diabetes: Yes | 0.1466 | 0.0634 | 0.0208 |
| Diabetes: No | REFERENT | – | – |
Footnotes:
1 Medical school affiliation is reported on the Annual Hospital Survey.
2 Based on NHSN enrollment as HOSP-ONC.
