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 receive payment from CMS, 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. Information for CMS reporting is currently collected through NHSN about central line-associated bloodstream infections, catheter-associated urinary tract infections, surgical site infections, MRSA Bacteremia and C.difficile Laboratory-identified Events. Future reporting will include healthcare worker influenza vaccination coverage and more. The public reporting of these data 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.
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 manually identify such infections. 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. The SIR may take into account the type of patient care location, number of patients admitted with MRSA or C. difficile, laboratory methods, hospital affiliation with a medical school, bed size of the hospital, patient age, and American Society of Anethesiologists' (ASA) classification of physical health. It compares the actual number of HAIs in a facility or state to a national benchmark based on previous years of reported data and adjusts the data based on several factors.
An overall SIR for the state is also calculated, 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 U.S. 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 U.S. 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 U.S. 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