2021 National and State Healthcare-Associated Infections Progress Report

2021 National and State Healthcare-Associated Infections Progress Report

The Centers for Disease Control and Prevention (CDC) is committed to protecting patients and healthcare personnel from adverse healthcare events and promoting safety, quality, and value in healthcare delivery.  Preventing healthcare-associated infections (HAIs) is a top priority for CDC and its partners in public health and healthcare. The 2021 annual National and State Healthcare-Associated Infections (HAI) Progress Report provides a summary of select HAIs across four healthcare settings: acute care hospitals (ACHs), critical access hospitals (CAHs), inpatient rehabilitation facilities (IRFs) and long-term acute care hospitals (LTACHs). Data from CAHs are provided in the detailed technical tables but not in the report itself. The designation of CAH is assigned by the Centers for Medicare and Medicaid Services (CMS) to hospitals with 25 or fewer acute care inpatient beds and that maintain an annual average length of stay of 96 hours or less for acute care patients. IRFs include hospitals, or part of a hospital, that provide intensive rehabilitation services using an interdisciplinary team approach. LTACHs provide treatment for patients who are generally very sick and stay, on average, more than 25 days. To view HAI data from individual hospitals, LTACHs and IRFs, please see CMS Care Compare

This report, along with the detailed technical tables, provides national- and state-level data about HAI incidence during 2021. The report is designed to be accessible to many audiences. National and state HAI reports will be available for viewing, downloading, and printing from the Antibiotic Resistance and Patient Safety Portal.  For detailed methods, references, and definitions, please refer to the Technical Appendix and Glossary within this report. For more information, please visit CDC’s Healthcare-Associated Infection Data Reports website.

CDC’s mission in healthcare safety includes tracking infections, responding to outbreaks, providing infection prevention expertise and guidance, implementing prevention interventions in collaboration with partners, spearheading prevention research, and serving as the nation’s gold standard microbiology laboratory for the pathogens most often implicated in HAIs. CDC’s National Healthcare Safety Network (NHSN), the nation’s most widely used HAI surveillance system, is a shared resource for HAI prevention. More than 38,000 active hospitals, long-term care facilities, and other healthcare facilities provide data to NHSN, which in turn is used for national- and state-level analyses, including for this HAI Report, and for targeted prevention initiatives by healthcare facilities, states, regions, quality groups, and national public health agencies, including CDC.

The 2021 National and State HAI Progress Report provides data on central line-associated bloodstream infections (CLABSIs), catheter-associated urinary tract infections (CAUTIs), ventilator-associated events (VAEs), surgical site infections (SSIs), methicillin-resistant Staphylococcus aureus (MRSA) bloodstream events, and Clostridioides difficile (C. difficile) events. For each of the four healthcare settings, the report consists of detailed technical tables, which include additional statistics about HAIs, reporting mandates, and data validation efforts in each state and select US territories. The report includes infection-specific standardized infection ratios (SIRs), which measure progress in reducing HAIs compared to the 2015 baseline time period. The SIR is the ratio of the observed number of infections (events) to the number of predicted infections (events) for a summarized time period. In addition to the SIRs, the report includes the standardized utilization ratios (SURs), which measure device use by comparing the number of observed device days to the number of predicted device days. The SIR and SUR metrics are calculated using the 2015 national baseline and risk adjustment methodology. More information about these metrics can be found at:

NHSN’s Guide to the SIR: https://www.cdc.gov/nhsn/pdfs/ps-analysis-resources/nhsn-sir-guide.pdf [PDF – 50 pages]

NHSN’s Guide to the SUR: https://www.cdc.gov/nhsn/pdfs/ps-analysis-resources/nhsn-sur-guide-508.pdf [PDF – 28 pages].

The Impact of COVID-19 on HAI Incidence in 2021

In 2021, the nation and the world continued to experience unprecedented challenges due to the COVID-19 pandemic, which impacted surveillance for and incidence of HAIs. Compared to pre-pandemic years, hospitals across the nation experienced higher than usual hospitalizations and shortages in healthcare personnel and equipment, which may have resulted in deterioration in multiple patient safety metrics since the beginning of the pandemic¹. In 2021, hospitals resumed mandated reporting for HAIs as the previously implemented extraordinary circumstance exception (ECE) policy ended with 2020Q2 data. As a result, the number of facilities reporting HAIs via NHSN returned to the pre-pandemic numbers in 2021 after a decline in 2020.

Findings from review of the quarterly 2021 NHSN data compared with2019 showed continued increases in 2021 in the quarterly SIRs for CLABSI, CAUTI, VAE, and MRSA bacteremia. Despite a decrease in the SIR for 2021Q2 compared to the preceding quarter, the SIRs for CLABSI, VAE, and MRSA bacteremia remained higher than in2019Q2. The 2021 quarterly SIRs for CDI showed significant decreases and the SSI-COLO, SSI-HYST SIRs remained largely unchanged.²

The results of the SIR analyses on an annual basis are parallel to the results of the quarterly analyses summarized above with the comparison year in the Progress Report is the year 2020. As with the quarterly SIR analyses, significant increases are observed for acute care facilities in the 2021 annual SIRs for CLABSI, CAUTI, MRSA, and VAE when compared with 2020. A significant decrease was observed in the C. difficile national SIR. In addition, the annual report found no significant change in the SSI in 2021 following colon surgery. Overall, the report shows a significant increase in SSI s in 2021 following abdominal hysterectomy when compared with 2020. Results of the 2021 annual HAI Progress Report are detailed subsequently.

This 2021 annual report includes national and state data for the following HAIs and facility types:

* National SSI data includes 39 inpatient surgical procedure categories reported to NHSN. For event and infection definition, see the HAI module specific NHSN protocols [PDF – 428 pages]

The number of states and territories that performed better than the 2015 national baseline by infection type:

The number of states and territories that performed worse than the 2015 national baseline, by infection type:

Each day, approximately one in 31 U.S. patients and 1 in 43 nursing home residents’ contracts at least one infection in association with their healthcare, underscoring the need for improvements in patient care practices in U.S. healthcare facilities. While much progress has been made, more needs to be done to prevent healthcare-associated infections in a variety of settings.

Full engagement between local, state and federal public health agencies and their partners in the healthcare sector through initiatives such as prevention collaboratives is vital to sustaining and extending HAI surveillance and prevention progress. CDC will continue its prevention, tracking, lab, and applied research activities to push the country further toward the goal of eliminating HAIs.

Any comments and suggestions that would improve the usefulness of future publications are appreciated and should be sent to the Division of Healthcare Quality Promotion, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road, Mailstop H16-3; Atlanta, Georgia, 30333. E-mail can also be used: patientsafety@cdc.gov.

2021 HAI Progress Report

National and State Factsheets are available via the Antimicrobial Resistance & Patient Safety Portal.

Data Tables

• 2021 SIR Data
  • 2021 National and State HAI Progress Report SIR Data – Acute Care Hospitals [XLS – 582 KB]
  • 2021 National and State HAI Progress Report SIR Data – Critical Access Hospitals [XLS – 341 KB]
  • 2021 National and State HAI Progress Report SIR Data – Inpatient Rehabilitation Facilities [XLS – 125 KB]
  • 2021 National and State HAI Progress Report SIR Data – Long-Term Acute Care Hospitals [XLS – 146 KB]
  • 2021 National HAI SIR Data – Pediatric and Oncology [XLS – 62 KB]

• 2021 SUR Data
  • 2021 National and State HAI Progress Report SUR Data – Acute Care Hospitals [XLS – 270 KB]
  • 2021 National and State HAI Progress Report SUR Data – Critical Access Hospital [XLS – 162 KB]
  • 2021 National and State HAI Progress Report SUR Data – Inpatient Rehabilitation Facilities [XLS – 91 KB]
  • 2021 National and State HAI Progress Report SUR Data – Long-Term Acute Care Hospitals [XLS – 93 KB]

Technical Appendix

The 2021 National and State Healthcare-Associated Infections Data Report presents data reported to the National Healthcare Safety Network (NHSN) for the calendar year 2021. The healthcare-associated infection (HAI) data were reported in response to state or federal reporting requirements (via the Centers for Medicare and Medicaid Services, CMS)^4-6, or were reported voluntarily, from healthcare facilities in all 50 states, Washington, D.C., Virgin Islands, Guam, and Puerto Rico. Data included in the annual report use standard NHSN definitions for central line-associated bloodstream infections (CLABSIs), catheter-associated urinary tract infections (CAUTIs), ventilator-associated events (VAEs), surgical site infections (SSIs), laboratory-identified (LabID) methicillin-resistant Staphylococcus aureus (MRSA) bloodstream events, and LabID Clostridioides difficile (C. difficile) events. ^7-11 To account for delays in reporting, 2021 data reported to NHSN through June 1, 2022, were included. The data used in preparing the report undergoes routine and rigorous data quality checks, which are part of NHSN’s processes. Addressing data quality issues is integral to NHSN’s ability to help facilities across the nation collect the data needed to identify areas needing prevention efforts, measure the progress of prevention efforts, monitor antibiotic use and resistance, and push toward HAI elimination. The NHSN Team routinely reviews the data reported to NHSN and will contact facilities to resolve confirmed and suspected data quality concerns. These data quality activities, which include data analyses and facility outreach, enhance the quality of the HAI data used in preparing this report.

National and state data included in this report are shown separately for acute care hospitals (ACHs), critical access hospitals (CAHs), long-term acute care hospitals (LTACHs), and inpatient rehabilitation facilities (IRFs, including CMS-certified IRF units within a hospital).

The national and state standardized infection ratios (SIRs) published in this report compare the observed number of infections occurring in 2021 and reported to NHSN with the predicted number of infections based on the 2015 national baseline and risk adjustment calculations. The risk adjustment methodology used to produce the CLABSI, CAUTI, VAE, SSI, MRSA bacteremia, and C. difficile SIRs for all facility types are summarized in NHSN’s SIR Guide.¹² SSI data were risk adjusted using a logistic regression model (CDC’s Complex Admission/Readmission model), and the device-associated (DA) and LabID event SIRs were risk adjusted using a negative binomial regression model.

This report also includes national and state standardized utilization ratios (SURs) to measure device utilization for central lines, urinary catheters, and ventilators among the four main facility types. The SUR provides a summarized risk adjusted metric which allows organizations to compare device use to a national 2015 baseline. SURs are calculated by dividing the number of observed device days by the number of predicted device days; the number of predicted device days is calculated using a logistic regression model. General information about SUR calculation can be found in NHSN’s Guide to the SUR.¹³

 SIRs and SURs are produced when at least five healthcare facilities reported 2021 data for the specific stratum, and at least one infection or device day is predicted to occur. The state-specific SIRs and SURs were calculated for each HAI and device type, location category or surgical procedure by pooling 2021 data from all reporting facilities in the state. A complete list of risk factors used in the calculation of all SIRs and SURs can be found in the technical Data Tables associated with this report. SIRs and SURs were assessed for statistical significance using a mid-p exact test for the 95% confidence interval (CI). The 95% CI is used in report to determine statistical significance when the SIR or SUR is compared to the value of 1. The 95% CI is a statistical range of values for which we have a high degree of confidence that the true SIR/SUR lies within that range. If the CI does not include 1, then the SIR/SUR is significantly different than 1.0 (i.e., the number of observed infections is significantly different than the number predicted). In the instances where the current year’s SIR or SUR is compared to the previous year’s SIR or SUR, a two-tailed p-value is used to determine statistical significance of the percent differences. A P-value of less than 0.05 was considered a statistically significant result. A P-value is considered inestimable for the following scenarios:

• if the previous year’s SIR or SUR is 0.000 and the current year’s SIR or SUR does not equal 0.000. The percent change is listed as >>100.0%
• if both the previous year’s SIR or SUR and the current year’s SIR or SUR are 0.000. The percent change is listed as 0%
• Comparison to the previous year is not performed if SIR or SUR data is missing.

The CLABSI, CAUTI, and VAE data are inclusive of data reported from all eligible locations within healthcare facilities, however the SIRs and SURs are also stratified by location type for critical care units (referred to as “ICUs”), neonatal critical care units (NICUs) (CLABSI only), and inpatient wards. For this report, “wards” included step-down units, mixed acuity units, and specialty care areas including hematology/oncology and bone marrow transplant units. The acute care hospital DA data are further stratified by specific CDC locations at the national level.

When sufficient data were available, national SSI SIRs were calculated for ACHs and CAHs for each of the 39 specific procedure categories defined by NHSN; the 10 select procedures that approximate the procedures included in the Centers for Medicare & Medicaid Services (CMS) Surgical Care Improvement Project (SCIP) are shown separately. National SIRs were stratified by adult and pediatric patients. State-level SSI SIRs were calculated for 15 select procedure types, including those within the SCIP and additional procedure categories with the highest volume of reported procedures. Due to insufficient pediatric SSI data at the state level, only adult SSI SIRs were calculated at the state level. Only deep incisional and organ/space SSIs, regardless of closure technique, detected during the same admission as the inpatient procedure or upon readmission to the same hospital that performed the inpatient procedure were included in the SSI SIRs; superficial incisional SSIs and those identified on post-discharge surveillance or upon readmission to another facility were excluded.

MRSA bacteremia and C. difficile LabID event SIRs included applicable specimens classified as hospital-onset (i.e., were collected on or after day 4 of admission) in which the specimen was collected from any inpatient location in the facility excluding CMS-certified inpatient psychiatric (IPF) units. C. difficile LabID event surveillance also excludes events from neonatal critical care units and well-baby units. Community-onset cases are reported to NHSN and are included in the risk adjustment of the LabID event SIRs.

National SIRs and SURs were calculated for all strata that met the inclusion criteria above. Each national metric was compared to the 2015 national baseline of 1 and was compared to the national metric from the prior year. Both comparisons provide information on a national level about the amount of device use and healthcare-associated infections in US hospitals.

Facility-specific SIRs and SURs were calculated if the facility had at least one predicted HAI (SIR), or device day (SUR). These facility-specific SIRs and SURs were used to create percentile distributions for each infection and device type if at least 20 facilities had sufficient data to calculate a SIR or SUR. Percentile distributions among the national data are shown in increments of 5, from 5-95%; key percentiles were calculated for state-level data (10%, 25%, 50%, 75%, 90%). Additionally, the facility-specific SIRs/SURs were compared to the nominal value equal to that of the same year’s National SIR, for each infection and device type, if at least 10 facilities in each category had sufficient data to calculate the metric, the percent of facilities with a SIR/SUR significantly higher or lower than the national value was calculated both nationally and by state.

Each state’s 2021 SIR was compared against three benchmarks to assess progress in HAI prevention: the current 2021 national SIR, the state’s SIR from 2020, and the 2015 national baseline (i.e., compared to a value of 1). The 2021 national SIR was re-calculated for each state-to-national comparison with that state’s data removed from the 2021 national SIR to ensure independence. This comparison was used to determine how the state’s SIR compared to that from the rest of the nation. A comparison between the state’s 2021 and 2020 SIRs provided information about HAIs in the state during 2021, and how this compared to the same state’s SIR from the prior year. The final comparison assesses the state’s 2021 SIR against the national 2015 baseline of 1. Together, the three benchmarks provide a complete assessment of each state’s progress in HAI prevention.

For all comparisons, a P-value less than 0.05 was considered statistically significantly different than the hypothesized value (e.g., 1 for comparison to the 2015 baseline); while two-tailed P-values were used for these comparisons and are more conservative than one-tailed P-values, significant results were interpreted as a directional change of “increase” or “decrease” based on the actual SIR values in the comparison. The three comparisons listed above were also performed and interpreted in the same manner for state-specific SURs.

Most healthcare facilities in the US were required to report select HAI data to NHSN in 2021 for participation in various CMS Quality Reporting Programs (QRPs) and Pay for Performance Programs.¹⁴ The table below provides additional details on these requirements:

2021 Required Data Elements for Participation in CMS Programs, by Facility Type

In addition to the NHSN data used to produce the SIRs in this report, the factsheets and the detailed technical tables, several external data sources were used to provide additional metrics. Several state health department HAI programs voluntarily provided CDC with the status and specific requirements of state HAI reporting mandates to NHSN and efforts to validate 2021 HAI data. An indicator for a state mandate was provided for mandates enacted by either the state health department or the state’s hospital association. Validation efforts were classified into two categories for each HAI type – data checked for quality and additional in-depth data review. The following criteria were used to assign credit to states that performed data quality checks: state health department had access to 2021 NHSN data, performed regular data cleaning/quality checks on at least 6 months of 2021 data prior to June 1, 2022, and contacted hospitals if data errors, outliers, or missing information were found. A state received credit for additional in-depth data review if the state performed an audit of their hospitals’ medical or laboratory records prior to June 1, 2022, meaning the state health department reviewed hospital records to confirm proper case ascertainment and data entry into NHSN. Validation efforts should be considered when evaluating an individual state’s performance. States that perform more vigorous data validation activities are more likely to find hospital records of infections, and therefore these states may have higher SIRs compared to states that do not perform validation. Not all state health departments have access to NHSN data or have access to NHSN data from every hospital included in this report. Data validation efforts were self-reported by state health departments to CDC and may vary between states.

References

1. Fleisher LA, Schreiber M, Cardo D, Srinivasan A. Health Care Safety during the Pandemic and Beyond – Building a System That Ensures Resilience. N Engl J Med. 2022 Feb 17;386(7):609-611. doi: 10.1056/NEJMp2118285. Epub 2022 Feb 12. PMID: 35148040.

2. Lastinger, L., Alvarez, C., Kofman, A., Konnor, R., Kuhar, D., Nkwata, A., . . . Dudeck, M. (2022). Continued increases in the incidence of healthcare-associated infection (HAI) during the second year of the coronavirus disease 2019 (COVID-19) pandemic. Infection Control & Hospital Epidemiology, 1-5. doi:10.1017/ice.2022.116

3. Weiner-Lastinger, L., Pattabiraman, V., Konnor, R., Patel, P., Wong, E., Xu, S., . . . Dudeck, M. (2021). The impact of coronavirus disease 2019 (COVID-19) on healthcare-associated infections in 2020: A summary of data reported to the National Healthcare Safety Network. Infection Control & Hospital Epidemiology,1-14. doi:10.1017/ice.2021.362.

4. Centers for Medicare and Medicaid Services. Hospital Inpatient Quality Reporting Program. Available at https://www.cms.gov/medicare/quality-initiatives-patient-assessment-instruments/hospitalqualityinits/hospitalrhqdapu.html. Accessed August 17, 2022.Inpatient Rehabilitation Facilities Quality Reporting Program. Available at https://www.medicare.gov/inpatientrehabilitationfacilitycompare/. Accessed August 17, 2022.Long-Term Acute Care Hospital Quality Reporting Program. Available at
   https://www.medicare.gov/longtermcarehospitalcompare/. Accessed August 17, 2022.

5. Centers for Medicare and Medicaid Services. Long-Term Care Hospital Quality Reporting. Available at https://www.cms.gov/Medicare/Quality-Initiatives-Patient-Assessment-Instruments/LTCH-Quality-Reporting/. Accessed August 17, 2022.

6. Centers for Medicare and Medicaid Services. Inpatient Rehabilitation Facilities (IRF) Quality Reporting Program (QRP). Available at https://www.cms.gov/Medicare/Quality-Initiatives-Patient-Assessment-Instruments/IRF-Quality-Reporting/index.html. Accessed August 17, 2022.

7. Centers for Disease Control and Prevention. Acute care hospital surveillance for central line-associated bloodstream infections. http://www.cdc.gov/nhsn/acute-care-hospital/clabsi/index.html. Accessed August 17, 2022.

8. Centers for Disease Control and Prevention. Acute care hospital surveillance for catheter-associated urinary tract infections. http://www.cdc.gov/nhsn/acute-care-hospital/cauti/index.html. Accessed August 17, 2022.

9. Centers for Disease Control and Prevention. Acute care hospital surveillance for surgical site infections. http://www.cdc.gov/nhsn/acute-care-hospital/ssi/index.html. Accessed August 17, 2022.

10. Centers for Disease Control and Prevention. Acute care hospital surveillance for C. difficile, MRSA, and other drug-resistant infections. Available at http://www.cdc.gov/nhsn/acute-care-hospital/cdiff-mrsa/index.html. Accessed August 17, 2022.

11. Centers for Disease Control and Prevention. Acute care hospital surveillance for Ventilator-associated Events (VAE). Available at https://www.cdc.gov/nhsn/acute-care-hospital/vae/index.html. Accessed August 17, 2022.

12. Centers for Disease Control and Prevention. The NHSN Standardized Infection Ratio (SIR): a guide to the SIR. Available at https://www.cdc.gov/nhsn/pdfs/ps-analysis-resources/nhsn-sir-guide.pdf [PDF – 50 pages]. Accessed August 17, 2022.

13. Centers for Disease Control and Prevention. The NHSN Standardized Utilization Ratio (SUR): a guide to the SUR. Available at https://www.cdc.gov/nhsn/pdfs/ps-analysis-resources/nhsn-sur-guide-508.pdf [PDF – 28 pages]. Accessed August 17, 2022.

14. Healthcare Facility HAI Reporting Requirements to CMS via NHSN – Current or Proposed Requirements. National Healthcare Safety Network website. https://www.cdc.gov/nhsn/pdfs/cms/cms-reporting-requirements.pdf [PDF – 2 pages ]. Accessed August 17, 2022.

Acknowledgements

We thank the infection preventionists, hospital epidemiologists, and other dedicated hospital and health department staff who work to support HAI surveillance and prevention measures. This report was prepared by the CDC’s National Center for Emerging and Zoonotic Infectious Diseases, Division of Healthcare Quality Promotion staff

Glossary

Terms and topics from CDC’s National and State Healthcare-Associated Infections Progress Report.

Click on the category to locate specific terms:
Organizations and Hospitals §  Infections Reported  §  Prevention Collaboratives  § Calculations

ORGANIZATIONS and HOSPITALS

Acute care hospital: a hospital is an institution that mainly provides diagnostic and therapeutic services to inpatients, including medical diagnosis, treatment, and care. The Centers for Medicare & Medicaid Services requires that all patients in hospitals be under the care of a physician and provided 24-hour nursing assistance.

Centers for Disease Control and Prevention (CDC): Housed within U.S. Department of Health and Human Services, CDC is charged with protecting the public health of the nation by providing leadership and direction in the prevention of and control of diseases and other preventable conditions and responding to public health emergencies. CDC works 24/7 to protect America from health, safety, and security threats, both foreign and in the U.S.

Emerging Infections Program (EIP): A national resource utilized for surveillance, prevention, and control of emerging infectious diseases. EIP is a network of state health departments and their collaborators in local health departments, academic institutions, other federal agencies, and public health and clinical laboratories; infection preventionists; and healthcare providers.

CMS Care Compare: A consumer-oriented website that provides information about the quality of care of various provider types such as doctors and clinicians, hospitals, nursing homes including rehab services, home health services, hospice care, IRF, LTACH and dialysis facilities. CMS Compare was created through the efforts of the Centers for Medicare & Medicaid Services (CMS), in collaboration with organizations representing consumers, hospitals, doctors, employers, accrediting organizations, and other Federal agencies. Hospitals participating in the CMS quality reporting program submit healthcare-associated infection data to CDC’s National Healthcare Safety Network (NHSN). NHSN shares these data with CMS for fulfillment of their Programs, including sharing data on CMS Care Compare to help consumers make informed decisions about their health care.

Inpatient rehabilitation facilities (IRF): Hospitals, or part of a hospital that provide intensive rehabilitation services using an interdisciplinary team approach. Admission to an IRF is appropriate for patients with complex nursing, medical management, and rehabilitative needs. Data in this report are reported from free-standing IRFs and CMS-certified IRF units within other hospitals.

Long-term acute care hospital (LTACH): Acute care hospitals that provide treatment for patients who are generally very sick and stay, on average, more than 25 days. Services include comprehensive rehabilitation, respiratory therapy, head trauma treatment, and pain management. Most patients are transferred from an intensive or critical care unit.

National Healthcare Safety Network (NHSN): CDC’s NHSN is the nation’s most widely used healthcare-associated (HAI) infection tracking system. NHSN provides facilities, states, regions, and the nation with data needed to identify problem areas, measure progress of prevention efforts, and ultimately eliminate HAIs. In addition, NHSN allows healthcare facilities to track blood safety errors and important healthcare process measures such as healthcare personnel influenza vaccine status and infection control adherence rates.

INFECTIONS REPORTED

Catheter-associated urinary tract infection (CAUTI): A urinary tract infection (UTI) is an infection involving any part of the urinary system, including urethra, bladder, ureters, and kidney. When a urinary catheter is not put in correctly, not kept clean, or left in a patient for too long, germs can travel through the catheter and infect the bladder and kidneys. In this report, the CAUTI data include all infections reported to National Healthcare Safety Network from all applicable locations, including intensive care units and wards.

Central line-associated bloodstream infection (CLABSI): When a tube is placed in a large vein and not put in correctly or kept clean, it can become a way for germs to enter the body and cause deadly infections in the blood. In this report, the CLABSI data include all infections reported to National Healthcare Safety Network from all applicable locations, including intensive care units, neonatal intensive care unit, and wards. 

 Clostridioides difficile (C. difficile): When a person takes antibiotics, good bacteria that protect against infection are destroyed for several months. During this time, patients can get sick from C. difficile, bacteria that can cause life-threatening diarrhea. Often, C. difficile infections occur in hospitalized or recently hospitalized patients. In this report, the C. difficile data include all laboratory identified hospital-onset infections reported to National Healthcare Safety Network from all inpatient locations in the facility, except for the neonatal intensive care units and well-baby locations.

Healthcare-associated infection (HAI): Infection patients can get while receiving medical treatment in hospitals, outpatient clinics, nursing homes, and other facilities where people receive care.

• Hospital-onset HAI: For reporting to National Healthcare Safety Network, a LabID event is considered hospital-onset if the patient begins to show infection symptoms on or after the fourth day of admission. For other HAIs, an infection is considered hospital-onset if the patient begins to show infection symptoms on or after the third day of admission.
• Laboratory identified (LabID) Event: For reporting to National Healthcare Safety Network, an infection is considered laboratory identified when a patient sample is tested and confirmed by laboratory test only (i.e., clinical evaluation of the patient is not required).

Methicillin-resistant Staphylococcus aureus (MRSA): A type of staph bacteria that is resistant to many antibiotics. In this report, the MRSA data include all laboratory identified hospital-onset MRSA bacteremia (bloodstream infections) reported to National Healthcare Safety Network from all inpatient locations in the facility.

Surgical site infection (SSI): When germs get into an area where surgery is or was performed, patients can get a surgical site infection. Sometimes these infections involve only the skin. Other SSIs can involve tissues under the skin, organs, or implanted material (an object or material inserted or grafted into the body, such as prosthetic joints).

PREVENTION COLLABORATIVES

Antibiotic stewardship: Coordinated efforts and programs to improve the use of antimicrobials in healthcare settings to ensure that hospitalized patients receive the right antibiotic, at the right dose, at the right time, and for the right duration.

Antibiotic resistance : Antibiotic resistance is the result of bacteria changing in ways that reduce or eliminate the effectiveness of antibiotics. 

Carbapenem-resistant Enterobacteriaceae (CRE) infections: A family of germs that is difficult to treat because they have high levels of resistance to antibiotics. CRE infections are most seen in people with exposure to healthcare settings, like hospitals and long-term care facilities. 

Hand hygiene: The practice of cleaning hands to prevent the spread of disease-causing germs. 

Healthcare personnel influenza vaccination: Influenza, or the flu, is a mild to severe respiratory illness caused by a virus. The contagious illness can easily spread from person to person, including from healthcare workers to patients. Vaccination is the best way to prevent getting and spreading the flu.  

Long-term care facilities (LTCF): Nursing homes, skilled nursing facilities, and assisted living facilities (collectively known as long-term care facilities) provide a variety of services, both medical and personal care, to people who are unable to manage independently in the community. 

Multidrug-resistant organism (MDRO) infections: An infection caused by germs that are resistant to multiple classes of antimicrobials. In some cases, the germs have become so resistant that no available antibiotics are effective against them.  

Prevention collaboratives: Prevention projects that consist of multiple healthcare facilities within a state or region to target an infection as a team, implement prevention strategies, share experiences between facilities, measure progress as a group, and provide feedback to clinicians and staff. 

Targeted Assessment for Prevention (TAP) strategy: A quality improvement framework developed by the Centers for Disease Control and Prevention (CDC) to use data for action to prevent healthcare-associated infections (HAIs). The TAP Strategy targets healthcare facilities and specific units within facilities with a disproportionate burden of HAIs to identify and address infection prevention gaps.  

Ventilator-associated events (VAE): A ventilator is a machine used to help a patient breathe by giving oxygen through a tube placed in a patient’s mouth or nose, or through a hole in the front of the neck. An infection may occur if germs enter a patient through the tube, such as pneumonia or bacterial infections in the blood.

CALCULATIONS

National baseline:

Aggregated data reported to the National Healthcare Safety Network (NHSN) by all facilities during a baseline period that is used to “predict” the number of infections expected to occur in a hospital, state, or in the country. In this report, the number of predicted infections is an estimate based on infections reported to NHSN during the 2015 national baseline for all facility types.

Standardized Infection Ratio (SIR): A summary statistic that can be used to track healthcare-associated infection (HAI) prevention progress over time; lower SIRs are better. The SIR compares the number of infections in a facility or state to the number of infections that were “predicted” to have occurred, based on previous years of reported data (see National baseline). The SIR is not calculated when the number of predicted infections is less than 1. In this report, the SIRs compare the observed number of infections reported to the National Healthcare Safety Network (NHSN) during 2021 to the predicted number of infections based on the 2015 referent period, adjusting for key risk factors.

• Risk adjustment: A process used to level the playing field by adjusting for the differences in risk. When the data are risk-adjusted, it makes it possible to fairly compare hospital performance. In this report, the SIRs are adjusted for risk factors that may impact the number of infections reported by a hospital, such as type of patient care location, bed size of the hospital, patient age, and other factors.
• National 2020 SIR: A summary statistic calculated from all reported HAIs that occurred in the country in 2021. It was calculated as the total number of observed infections in the country, divided by the total number of predicted infections in the country in 2021.
• State 2020 SIR: A summary statistic calculated from all reported HAIs that occurred in an individual state in 2021. It was calculated as the total number of observed infections from all hospitals in the state, divided by the total number of predicted infections in the state in 2021.

Standardized Utilization Ratio (SUR):

A summary statistic that can be used to track device utilization over time; lower SURs are better. The SUR compares the number of device days (central lines, urinary catheters, ventilators) in a facility or state to the number of device days that were “predicted” to have occurred, based on previous years of reported data (see National baseline). The SUR is not calculated when the number of predicted device days is less than 1. In this report, the SURs compare the observed number of device days reported to the National Healthcare Safety Network (NHSN) during 2021 to the predicted number of device days based on the 2015 referent period, adjusting for key risk factors.

State mandate (for data reporting): A state legislative or regulatory requirement (enacted by the state’s government or promulgated by a state agency) requiring hospitals (and other healthcare facilities) in the state’s jurisdiction to report healthcare-associated infections to the National Healthcare Safety Network.

Validation: Double-checking, or confirming, healthcare-associated infection (HAI) data reported to the National Healthcare Safety Network (NHSN). This generally involves an assessment to ensure all relevant infections were captured in the system. It may also involve checking the accuracy, or quality, of the submitted data. Currently, state health departments may use different methods to validate the HAI data that hospitals submit to NHSN. For example, some states only validate data from one facility while other states validate more widely. Validation efforts should be considered when evaluating an individual state’s performance. States that validate data or use advanced tools to detect HAIs may find and report more infections than states that do not validate. In this report, state validation efforts are specified and classified into two categories for each HAI type: data checked for quality and additional in-depth data review.

“Additional In-depth Data Review”: State health departments may perform a review, or “audit”, of a hospital’s medical records to ensure the hospital defined and reported all appropriate HAIs to NHSN. The auditing process may identify more HAIs in a hospital than originally reported. As such, states that perform data audits may have a higher SIR when compared to states that do not perform data audits. In this report, credit is given to states that performed any type of audit of their hospitals’ 2021 medical or laboratory records prior to June 1, 2022.