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CDC's Healthcare-associated Infection Progress Report: Questions and Answers

HAI Progress Report Data

HAI Progress Report

CDC’s National Healthcare Safety Network (NHSN) enables healthcare facilities to collect and report healthcare-associated infection (HAI) data. CDC, states, healthcare facilities, and other patient safety organizations use this data to identify problem areas, measure progress of prevention efforts, and ultimately eliminate HAIs.

About the Report

Report Findings

Prevention Initiatives

For the HAI Progress Report, including data tables and glossary, visit www.cdc.gov/hai/progress-report.


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About the Report

» What is the healthcare-associated infection (HAI) progress report?


CDC’s HAI progress report is a snapshot of how each state and the country are doing in eliminating HAIs. Each report describes the progress in preventing the following types of HAIs:

  • Central line-associated bloodstream infections (CLABSIs) happen when a central line (a tube that a doctor usually places in a large vein of a patient’s neck or chest to give important medical treatment) is not put in correctly or not kept clean. This allows the central line to become a freeway for germs to enter the body and cause serious bloodstream infections.
  • Surgical site infections (SSIs) are infections that occur after surgery in the part of the body where the surgery took place.
  • Catheter-associated urinary tract infections (CAUTIs) are infections that involve 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.
  • Hospital-onset Clostridium difficile (C. difficile) infections can cause life-threatening diarrhea. This report only includes laboratory identified hospital-onset infections reported.
  • Hospital-onset methicillin-resistant Staphylococcus aureus (MRSA) bacteremia (bloodstream infections) is caused by a type of staph bacteria that is resistant to many antibiotics. This report only includes laboratory identified hospital-onset infections reported.

Each report is based on data reported to the CDC’s National Healthcare Safety Network (NHSN). NHSN provides a secure way for healthcare facilities to track HAIs and take action to prevent infections. Progress is measured using the standardized infection ratio (SIR), a summary statistic that can be used to track HAI prevention progress over time. Researchers use the reported HAI data to calculate a standardized infection ratio (SIR) for each reporting state and facility.

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» What are the benefits of reporting healthcare-associated infection data?


Research shows that when healthcare facilities, care teams, and individual practitioners are aware of infection problems and take specific steps to prevent them, rates of certain HAIs can decrease by more than 70 percent. Infection data can give healthcare facilities and public health agencies information they need to design, implement, and evaluate prevention strategies that protect patients and save lives.

CDC fully supports public reporting of HAI data as an important part of overall healthcare transparency efforts and of national HAI elimination.

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» How can I use this report to help prevent healthcare-associated infections?


This report is a useful tool for federal, state, and local government; healthcare facilities; and patient safety organizations and advocates all of whom can use these data to lower HAI rates.

Use this report to:

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» What makes the National Healthcare Safety Network (NHSN) a good measurement tool?


With more than 14,500 healthcare facilities participating, NHSN is the largest HAI reporting system in the United States. NHSN provides standard methods and definitions, online training modules, user support, and facility comparison tools. Nearly all U.S. hospitals and dialysis facilities are able to successfully report to NHSN, making it an important tool for national HAI tracking and elimination.

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Report Findings

» Have we made progress in reducing central line-associated bloodstream infections?


As of 2013, CLABSIs are down nationally by 46 percent since 2008.The current report shows a national decrease in central line-associated bloodstream infections (CLABSIs). As of 2013, CLABSIs are down nationally by 46 percent since 2008. These encouraging findings reflect the work of care teams, individual practitioners, and facilities; local, state, and federal government; and cross-cutting partnership groups that have taken on CLABSI prevention efforts. We hope that all states and healthcare facilities will be motivated to continue and strengthen efforts to prevent CLABSIs.

HHS has set a goal of reducing CLABSIs nationally by 50 percent by the end of 2013.A central line is a narrow tube placed in a large vein of a patient’s neck or chest to give important medical treatment. When not put in correctly or not kept clean, a central line can become a highway for germs to enter the body and cause a serious bloodstream infection.

HHS set a goal of reducing CLABSIs nationally by 50 percent by the end of 2013.


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» Have we made progress in reducing surgical site infections?


As of 2013, surgical site infections (SSIs) are down nationally by 19 percent since 2008As of 2013, surgical site infections (SSIs) from 10 select procedures are down nationally by 19 percent since 2008; however, there is a wide variation in SSI rates for specific surgical procedures. US hospitals reported a significant decrease in the number of SSIs between 2012 and 2013 from 4 procedure types: hip arthroplasty, knee arthroplasty, coronary artery bypass graft, and peripheral vascular bypass graft. While these results are encouraging, we, as a healthcare community, still have opportunities to improve prevention efforts across many surgical procedures.


HHS has set a goal of reducing SSIs nationally by 25 percent by the end of 2013.The report includes a national snapshot of the infection risk linked to the following common surgical procedures:

  • Hip or knee arthroplasty
  • Coronary artery bypass graft
  • Cardiac surgery
  • Peripheral vascular bypass surgery
  • Abdominal aortic aneurysm repair
  • Colon or rectal surgery
  • Abdominal or vaginal hysterectomy

HHS set a goal of reducing SSIs nationally by 25 percent by the end of 2013.

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» Have we made progress in reducing catheter-associated urinary tract infections?


As of 2013,  catheter-associated urinary tract infections (CAUTIs) are up nationally by 6 percent  since 2009.As of 2013, catheter-associated urinary tract infections (CAUTIs) are up nationally by 6 percent since 2009. CAUTIs have continued to increase between 2012 and 2013; although initial data from 2014 seem to indicate that these infections have started to decrease.


HHS has a goal of reducing CAUTIs nationally by 25  percent by the end of 2013.Reducing CAUTI among critical care patients is a special concern because these infections drive antibiotic use. While antibiotics are essential for treating bacterial infections, they also increase patients’ risk for complications. One potentially deadly complication is severe diarrhea caused by the bacteria Clostridium difficile.

HHS set a goal of reducing CAUTIs nationally by 25 percent by the end of 2013.


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» Have we made progress in reducing hospital-onset Clostridium difficile infections?


As of 2013,  hospitalonset Clostridium difficile infections (CDIs) are down nationally by 10% since 2011, which will serve as the  comparison year for CDIs in the National Action Plan.As of 2013, hospital-onset Clostridium difficile infections (C. difficile) are down nationally by 10 percent since 2011.


HHS has set a goal of reducing hospitalonset Clostridium difficile infections nationally by 30 percent by the  end of 2013.When a person takes or is administered antibiotics, good bacteria that protect against infection are destroyed for several months. During this time, patients can get sick from Clostridium difficile, bacteria that cause potentially deadly diarrhea.

HHS set a goal of reducing hospital-onset Clostridium difficile infections nationally by 30 percent by the end of 2013.


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» Have we made progress in reducing hospital-onset methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infections?


As of 2013, hospital-onset MRSA bloodstream infections are down nationally by 8% since 2011, which will serve as the comparison year for MRSA bloodstream infections in the National Action Plan.As of 2013, hospital-onset MRSA bloodstream infections are down nationally by 8 percent since 2011.


HHS has set a goal of reducing hospital-onset Clostridium difficile infections nationally by 30 percent by the  end of 2013.MRSA is a type of staph bacteria that is resistant to many antibiotics, usually spread by direct contact with an infected wound or from contaminated hands. In a healthcare setting, such as a hospital or nursing home, MRSA can cause serious bloodstream infections.

HHS set a goal of reducing hospital-onset MRSA bloodstream infections nationally by 25 percent by the end of 2013.


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» What is the standardized infection ratio?


The standardized infection ratio (SIR) is a summary measure that can be used to track HAI prevention progress over time; lower SIRs are better.

The CDC adjusts the SIR for risk factors that are most associated with differences in infection rates. In other words, the SIR takes into account the fact that different healthcare facilities treat different types of patients. For example, HAI rates at a hospital that a large burn unit (where patients are at higher risk of acquiring infections) cannot be directly compared to a hospital that does not have a burn unit.

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» What does the standardized infection ratio number mean?

If the SIR is more than 1:Thumbsup

There was an increase in the number of infections reported in the nation compared to the national baseline.

  • A high SIR usually reflects a need for stronger HAI prevention efforts.
  • Other factors may also play a role in a high SIR, such as intense data validation activities that lead to the discovery and reporting of more infections than in previous years.

If the SIR is 1:Thumbsup

There were about the same number of infections reported in the nation compared to the national baseline.

If the SIR is less than 1:Thumbsup

There was a decrease in the number of infections reported in the nation compared to the national baseline.

  • Usually, a low SIR reflects the results of robust HAI prevention strategies. These scenarios are exciting, and CDC is working with facilities and states to learn and share best practices.
  • CDC is also considering the degree, if any, of underreporting in the data.
  • It is important to note that this report is not meant to compare states – it is meant to track the results of each state’s prevention efforts over time.
  • It is also important to note that while an SIR of less than 1 is a positive finding, it does not mean the work is done. We have made progress toward reducing infections, but research shown that we can reduce HAI rates even more.

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» How does the CDC calculate the standardized infection ratio?


The SIR compares the number of infections in a facility or state to the number of infections that were “predicted”, or would be expected, to have occurred based on previous years of reported data (national baseline).

The national 2013 SIR is a summary statistic calculated from all reported HAIs that occurred in the country in 2013. 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 2013.  

The state 2013 SIR is a summary statistic calculated from all reported HAIs that occurred in an individual state in 2013. 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 2013.  

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» How is the SIR adjusted for 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. The SIR is adjusted differently depending on the type of infection measured.

The SIRs for CLABSIs and CAUTIs are adjusted for:

  • Type of patient care location
  • Hospital affiliation with a medical school
  • Bed size of the patient care location

The SIRs for hospital-onset C. difficile and MRSA bloodstream infections are adjusted using slightly different risk factors:

  • Facility bed size
  • Hospital affiliation with a medical school
  • The number of patients admitted to the hospital who already have C. difficile or an MRSA bloodstream infection (“community-onset” cases)
  • For hospital-onset C. difficile, the SIR also adjusts for the type of test the hospital laboratory uses to identify C. difficile from patient specimens.

The SIRs for SSIs take into account patient differences and procedure-related risk factors within each type of surgery. These risk factors include:

  • Duration of surgery
  • Surgical wound class
  • Use of endoscopes
  • Re-operation status
  • Patient age
  • Patient assessment at time of anesthesiology

» What is the “predicted number of infections”?


The national baseline is aggregated data reported to NHSN by all facilities during a baseline period 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 following time periods:

  • 2006 to 2008: CLABSI and SSI
  • 2009: CAUTI
  • 2010 to 2011: MRSA bacteremia and C. difficile infections

Infection types presented have different baseline years for comparison. Moving forward, HAI prevention progress for 2016 and subsequent years will be measured in comparison to infection data from 2015.  

The number of predicted infections is risk-adjusted and includes data from all facilities, whether or not they are under state mandates. To calculate a state or facility’s SIR for a certain time period, CDC compares the predicted number of infections based on the standard population to the number of infections reported in that time period.

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Prevention Initiatives

» How many healthcare facilities have a high standardized infection ratio?


For each major HAI type, between 3 percent and 13 percent of the facilities in the country reported an SIR significantly greater than the national SIR in each category.

The following table shows the total number of facilities that had an SIR significantly greater than the national SIR for different types of HAIs. These numbers are relatively small compared to the total number of facilities that reported data in 2013.

Type of HAI Number of facilities with high SIR for this HAI in 2013
Central line-associated bloodstream infections (CLABSIs) 216
Catheter–associated urinary tract infections (CAUTIs) 332
Surgical site infections (SSIs) associated with hip arthroplasty 25
Surgical site infections (SSIs) associated with knee arthroplasty 21
Surgical site infections (SSIs) associated with colon surgery 151
Surgical site infections (SSIs) associated with abdominal hysterectomy 44
Hospital–onset Clostridium difficile infections 472
Hospital-onset MRSA bloodstream infections 150

In coming years, we can focus prevention efforts on these facilities to make more efficient use of resources.

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» What is CDC doing about healthcare facilities with high standardized infection ratios?


CDC is contacting these facilities and connecting them with prevention initiatives such as:

  • State health department collaboratives
  • Comprehensive Unit-based Safety Program (CUSP)
  • Partnership for Patients
  • CMS Quality Improvement Organizations

By moving these hospitals towards more prevention, we hope to see greater national reductions in HAIs next year.

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» What is CDC doing about states with high standardized infection ratios?


CDC is taking a proactive approach with all states. We offer training and technical assistance to help states identify and assist healthcare facilities whose performance does not show effective prevention work. We encourage states to monitor their SIR so they can aid prevention efforts in problem areas and measure the effects of prevention work over time.

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» What is data validation and why is it important?


Validation is double-checking, or confirming, healthcare-associated infection (HAI) data reported to the National Healthcare Safety Network (NHSN). Validating data usually includes completing an assessment to ensure that all relevant infections were captured in the system. It may also involve checking the accuracy, or quality, of the submitted data.

  • CDC encourages healthcare facilities and states to validate the infection data they submit to NHSN.
  • Currently, state health departments use different methods to validate HAI data that hospitals submit to NHSN. For example, some states only validate data from one facility while other states validate more widely.
  • CDC is working with states to determine best practices and develop effective validation standards.

To learn more about validation definitions used in the current HAI Progress Report, visit the Glossary within the report.

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» Will states that validate data have higher standardized infection ratios?


Validation efforts should be taken into account 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.

  • Healthcare facilities in states that validate data may have greater familiarity and experience using the NHSN protocol, and they may adhere to that protocol more scrupulously knowing that their data may be subject to external validation.  
  • Not all state health departments have access to NHSN data or have access to NHSN data from every hospital included in this report.

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