B6 - Partners - after HAI

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CDC’s Healthcare-Associated Infection Progress Report:
Questions and Answers
About the Reports
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 and advocates use this data to
identify problem areas, measure progress of prevention efforts,
and ultimately eliminate HAIs.

About the Reports
What is the healthcare-associated infection progress report?
How is this report used to prevent healthcare-associated infections?
What is the benefit of reporting healthcare-associated infection data?
What makes the National Healthcare Safety Network a good
measurement tool?

Report Findings
Has progress been made in reducing central line-associated
bloodstream infections?
Has progress been made in reducing surgical site infections?
Has progress been made in reducing catheter-associated urinary
tract infections?
What is the standardized infection ratio?
How is the standardized infection ratio calculated?
What does the standardized infection ratio number mean?
What is the “predicted number of infections”?
How many healthcare facilities had high standardized
infection ratios?

Prevention Initiatives
How many healthcare facilities have a high standardized infection ratio?
What is CDC doing about healthcare facilities with high standardized
infection ratios?
What is CDC doing about states with high standardized infection ratio?
What is data validation and why is it important?
Will states that look harder for infections have higher standardized
infection ratios?

What is the healthcare-associated infection progress report?
CDC’s HAI progress report gives a snapshot of how each state and the
country is doing in eliminating HAIs. These reports describe the progress in
preventing for the following types of HAIs:
• Central line-associated bloodstream infections (CLABSI) 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) isn’t put in
correctly or 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 (SSI) are infections that occur
after surgery in the part of the body where the surgery took place.
• Catheter-associated urinary tract infections (CAUTI)
are infections that involve any part of the urinary system,
including urethra, bladder, ureters, and kidney.
The reports are based on data reported to the CDC’s NHSN. NHSN provides
a secure way for healthcare facilities to track HAI data. Researchers use the
data to calculate a standardized infection ratio (SIR) for each reporting state
and facility.

How is this report used to prevent healthcare-associated
infections?
Federal, state, and local government; healthcare facilities; and patient safety
organizations and advocates can use these data to lower HAI rates.
• From a national perspective, the data measure progress toward the HAI
prevention goals outlined in the U.S. Department of Health and Human
Services (HHS) Action Plan to Prevent Healthcare-associated Infections .
• At the state level, the information helps assess the impact of state-based
HAI prevention programs. It also indicates any local facilities that have
significantly more infections than others in the area.

What is the benefit of reporting
healthcare-associated infection data?
Research shows that when healthcare facilities and clinicians
are aware of infection problems and take specific steps to
prevent them, rates of certain HAIs can decrease by
more than 70 percent.

70%

Infection data can give healthcare facilities and public health agencies
the knowledge they need to design, implement, and evaluate prevention
strategies that protect patients and save lives.
CDC believes that public reporting of HAI rates is an important part
of overall healthcare transparency efforts and of national HAI elimination.

What makes the National Healthcare
Safety Network a good measurement tool?
With more than 12,000 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.

Report Findings
Have we made progress in reducing central
line-associated bloodstream infections?
The reports show a national decrease in the
incidence of central line-associated
bloodstream infections (CLABSI). As of 2011,
CLABSIs are down nationally by 41 percent.
These encouraging findings reflect the work
of clinicians 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 CLABSI.

41%

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

50%

Have we made progress in reducing
surgical site infections?
As of 2011, surgical site infections (SSI) are
down nationally by 17 percent; however, there is a wide
variation in SSI rates for specific surgical procedures. In
hospitals who have been continuously reporting to CDC’s
NHSN, only SSIs following hip arthroplasty decreased from
2010 to 2011. This means we, as a healthcare community,
have substantial opportunities to improve prevention efforts
across many surgical procedures.

17%

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

25%

Have we made progress in reducing
catheter-associated urinary tract infections?
As of 2011, catheter-associated urinary tract
infections (CAUTI) are down nationally by 7
percent. The reports show a national decrease
in (CAUTI) from 2009 to 2010. There was no
additional reduction from 2010 to 2011. CAUTI
rates were down moderately among patients in general
wards, but there was basically no reduction of CAUTI rates
in critical care patients between 2010 and 2011.

7%

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 has a goal of reducing CAUTI nationally
by 25 percent by the end of 2013.

25%

What is the standardized infection ratio?
The standardized infection ratio (SIR) is a summary measure used to
track HAI over time. It compares actual HAI rates in a facility or state with
baseline rates in the general U.S. population. 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 that different healthcare
facilities treat different types of patients. For example, HAI rates at a
hospital that has a large burn unit (where patients are at higher risk
of acquiring infections) can’t be directly compared to a hospital that
doesn’t have a burn unit.

How does the CDC calculate the standardized
infection ratio?
The method of calculating an SIR is similar to the method of calculating
the standardized mortality ratio (SMR), a statistic that’s widely used by
public health researchers to analyze mortality data.
The SIR is adjusted differently depending on the infection rate being
measured. The SIR for CLABSI and CAUTI are adjusted by:
• Type of patient care location
• Hospital affiliation with a medical school
• Bed size of the patient care location
Other factors, such as facility bed size, aren’t associated with differences
in the SIR, so they aren’t part of the risk adjustment.
The SIR for SSI takes into account all known procedure-related risk
factors, in order to adjust for patient differences within each type of
surgery. Surgical risk factors include:
• Duration of surgery
• Surgical wound class
• Use of endoscopes
• Re-operation status
• Patient age
• Patient assessment at time of anesthesiology

What does the standardized infection ratio number mean?
If the SIR is less than 1:
• Infection rates have decreased since the baseline period.
• The number of infections reported in 2011 is lower than the number of
predicted infections.
• Usually, low SIR reflect 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’s important to note that these reports aren’t meant to compare
states — they’re meant to track the results of each state’s prevention
efforts over time.
• It’s also important to note that while an SIR of less than 1 is a positive
finding, it doesn’t mean the work is done. We’ve made progress toward
reducing infections, but research has shown that we can reduce HAI
rates even more.
If the SIR is 1:
• No progress has been made toward reducing infections since the
baseline period.
• The number of infections reported in 2011 is the same as the number
of predicted infections.
If the SIR is greater than 1:
• Infection rates have increased since the baseline period. The number
of infections reported in 2011 is higher than the number of predicted
infections.
• 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 data validation
that leads to the discovery and reporting of more infections than in
previous years.

The CDC uses the SIR to figure out the percent change in infection rates
for each type of HAI. The table below shows the method for calculating the
percent change.
To calculate a percent REDUCTION
(SIR less than 1):

To calculate the percent INCREASE
(SIR greater than 1):

1 minus the SIR = percent reduction.

SIR minus 1 = percent increase.

For example, with an SIR of 0.80:
1.00 – 0.80 = 0.20
0.20 = 20 %

For example, with an SIR of 1.25:
1.25 – 1.00 = 0.25
0.25 = 25 %

So, an SIR of 0.80 means there was
a 20% reduction in 2011 from the
baseline period.

So, an SIR of 1.25 means there was
a 25% increase in 2011 from the
baseline period.

What’s the “predicted number of infections”?
The predicted number of infections (also called the standard population) is
an estimate based on infections reported to NHSN in January 2006 through
December 2008. The number is risk-adjusted and includes data from all
facilities, whether or not they’re under state mandates. To calculate a
state or facility’s SIR for a certain time period, CDC compares the standard
population number to the number of infections reported in that time period.

Prevention Initiatives
How many healthcare facilities
have a high standardized infection ratio?
In each major location group and procedure category, between 2% and
9% of the facilities reported SIR significantly greater than 1. An SIR greater
than 1 means that more infections were observed than predicted.
The following table shows the total number of facilities that had an SIR
significantly greater than 1 for different types of HAIs. These numbers are
relatively small compared to the total number of facilities that reported
data in 2011.
Type of HAI

Number of facilities with
high SIR for this HAI in 2011

Central line-associated
bloodstream infections (CLABI)

54

Catheter-associated urinary
tract infections (CAUTI)

133

Surgical site infections (SSI)
associated with hip arthroplasty

25

Surgical site infections (SSI)
associated with knee arthroplasty

30

Surgical site infections (SSI)
associated with colon surgery

20

Surgical site infections associated
with abdominal hysterectomy

15

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

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 HAI next year.

What is CDC doing about states
with high standardized infection ratio?
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 doesn’t show effective prevention work.
We encourage states to monitor their SIR so they can aid prevention
efforts in problems areas and measure the effects of prevention work
over time.

What is data validation and why is it important?
CDC encourages healthcare facilities and states to validate (double-check)
the infection data they submit to NHSN. Validating data usually involves
completing an assessment to ensure that all relevant infections were
captured in the system.
Currently, different states use different systems to validate data. For
example, some states only double-check the data from one facility while
other states double-check more widely. CDC is working with states to
determine best practices and develop effective validation standards.

Will states that look harder for infections
have higher standardized infection ratios?
States that validate data and use other advanced tools for detecting
HAI are likely to discover and report more infections than states that
don’t use such tools. The reports indicate which states are validating
data, so those efforts can be taken into account when the state’s
performance is evaluated.