The healthcare-associated infection (HAI) measures show how often patients in a particular hospital contract certain infections during the course of their medical treatment, when compared to like hospitals. These infections can often be prevented when healthcare facilities follow guidelines for safe care. To get payment from Medicare, hospitals are required to report data about some infections to the Centers for Disease Control and Prevention’s (CDC’s) National Healthcare Safety Network (NHSN)- Opens in a new window. Hospitals currently submit information on central line-associated bloodstream infections (CLABSIs), catheter-associated urinary tract infections (CAUTIs), surgical site infections (SSIs), MRSA Bacteremia, and C.difficile laboratory-identified events. The public reporting of these data on Hospital Compare is part of a movement by the Department of Health and Human Services to make healthcare safer.
Which patients are included
The HAI measures apply to all patients treated in acute care hospitals, including adult, pediatric, neonatal, Medicare, and non-Medicare patients, unless otherwise noted below:
- CLABSI and CAUTI data include infections that occurred in patients in intensive care units (ICUs), neonatal ICUs (for CLABSI only), and medical, surgical, and medical/surgical ward locations.
- SSI data include those infections identified in adult patients ≥ 18 years of age.
- MRSA bacteremia and C.difficile data include those infections identified in all patients within the hospital.
Where the information comes from
CDC is in charge of tracking and preventing HAIs, and acute care hospitals are required to report these data to the CDC through the NHSN. The NHSN is a free web-based tool hospitals use to input the required information. For many HAI measures, hospitals have the ability to transmit data electronically directly from electronic health record (EHR) systems or EHR components. Most hospitals that track the incidence of HAIs still rely on infection preventionists to identify such infections manually. CDC provides training for NHSN users in standard surveillance methods. However, adherence to those standard methods varies from hospital to hospital, which may account for some inter-facility differences in the quality and completeness of the reported data. Validation programs are the primary means for addressing variation in data quality.
Calculations and risk adjustment
Calculations for the HAI measures adjust for differences in the characteristics of hospitals and patients using a Standardized Infection Ratio (SIR). The SIR is a summary measure that takes into account differences in the types of patients a hospital treats. Information about the SIR and its calculation can be found in NHSN’s Guide to the SIR. Below is a complete list of all variables included in the risk adjustment for acute care hospitals for each measure, starting with 2015 data. For information about historical risk adjustment on data prior to 2015, please see the NHSN website.
|CLABSI in ICUs and select wards||
|CAUTI in ICUs and select wards||
|SSI from colon surgery||
|SSI from abdominal hysterectomy||
|MRSA Blood Laboratory-identified Events (Bloodstream infections)||
|C.diff. Laboratory-identified Events (Intestinal infections)||
An overall SIR is also calculated for the state, which compares the total number of reported HAIs in the state to a national benchmark based on previous years of reported data. The state SIR is risk adjusted in the same manner described above.
A confidence interval with a lower and upper limit is displayed around each SIR to indicate that there is a high degree of confidence that the true value of the SIR lies within that interval. An SIR with a lower limit that is greater than 1.0 means that there were more HAIs in a facility or state than were predicted, and the facility is classified as "Worse than the National Benchmark". If the SIR has an upper limit that is less than 1, then the facility had fewer HAIs than were predicted and is classified as "Better than the National Benchmark". If the confidence interval includes the value of 1, then there is no statistical difference between the actual number of HAIs and the number predicted, the facility is classified as "No Different than National Benchmark". If the number of predicted infections is less than 1, the SIR and confidence interval cannot be calculated.
For more details on how the SIR is calculated, please refer to the CDC’s National Healthcare Safety Network.- Opens in a new window
More information about the updated baseline data used to calculate the SIRs is available on the CDC website.