Healthcare-associated infections (HAIs) are among the top causes of unnecessary illnesses and deaths in the United States. HAIs are infections that patients get while staying in a hospital or other healthcare facility – infections that the patients did not have before being admitted. They account for approximately 1.7 million infections and almost 100,000 deaths annually¹. HAIs result in extra days of hospitalizations and higher health care costs. The estimated financial impact of HAIs is between $28 billion to $33 billion a year².

HAIs and patient safety are major public health issues that require collaborations of government and the health care industry. Reducing HAIs is a priority for the State and for New Jersey hospitals. Signed in 2007, Public Reporting Legislation (PL of 2007, C 196) requires hospitals to report HAI data to the State Department of Health for public reporting in the Hospital Performance Report.

This section of the report shows how well New Jersey hospitals are providing safe patient care by comparing hospital’s HAI experience with the national experience. It gives hospitals information to help reduce HAIs and improve patient safety.

The HAI measures are calculated differently than the PSI measures. The HAIs are not reported as scores or simple percentages; they are reported as Standardized Infection Ratios (SIR). More detailed explanations on SIR are provided below. Hospitals that performed better than the national experience have lower ratios. Lower ratios are better because they suggest fewer infections. The green downward arrow symbol in the dashboard tables identifies the better performing hospitals. Similar to PSIs, a lower ratio is better.

This year’s report focuses on the following HAIs; Surgical Site Infections (SSIs) following Coronary Artery Bypass Graft (CABG), Abdominal Hysterectomy, Knee Arthroplasty and Colon surgery procedures, Central Line-Associated Bloodstream Infections (CLABSIs), and Catheter-Associated Urinary Tract Infections (CAUTIs).

New Jersey acute care hospitals are required to report SSI, CLABSI, and CAUTI infections to the National Healthcare Safety Network (NHSN), a healthcare-associated infection surveillance and tracking system developed by the Centers for Disease Control and Prevention (CDC). 

This report contains CLABSI, CAUTI and SSI data submitted to NHSN by New Jersey hospitals in 2023. Hospitals were provided the opportunity to verify the accuracy of their data. The data in this report have not been independently audited and validated.

Some hospitals treat sicker or older patients than others. Sicker patients in the hospitals’ Intensive Care Units (ICUs) are more likely to develop hospital-acquired infections. Hospitals affiliated with a medical school generally treat sicker patients than most hospitals. Also, not all hospitals have the same types of ICUs. For example, patients in burn units or trauma units are more at risk of acquiring infections. These differences make it difficult to fairly compare hospital’s HAI experience. 

The CDC uses a statistical method called “risk-adjustment” that standardizes the differences across hospitals and allows all hospitals to be measured more fairly (see NHSN SIR Guide). This method ‘adjusts’ for risk-factors that most often affect the risks of developing infections, such as type of ICUs, number of ICU beds, and hospitals affiliated with a medical school. This risk adjustment methodology was used on the New Jersey data to “even out the playing field”.

The Standardized Infection Ratio (SIR) is used to measure HAIs. The SIR is a summary measure developed by CDC to track HAIs at a national, state, local or hospital level over time (see NHSN SIR Guide).  The hospital SIR is the total number of “observed” or actual events, also called infections, divided by the total number of “expected” events, which is derived from the national baseline experience. More detailed explanations of the “observed” and “expected” number of events, as well as the SIR are provided below. 

The hospital SIRs are compared to the national experience, which is a baseline SIR of 1.0. The results are summarized under the column, Hospital to National Comparison.  This column classifies the hospitals’ performances by a green downward arrow as “Lower than Expected”, a gray horizontal arrow as “Similar to Expected”, or a red upward arrow as “Higher than Expected”. 

A hospital has performed better than the national baseline if the Hospital to National Comparison column is marked with a green downward arrow.  These hospitals appear better because they had fewer infections than what was predicted based on the national experience.  Hospitals labeled with a red upward arrow had more infections than what the national experience predicted.  Those hospitals that performed the same as the national experience are labeled with a gray horizontal arrow. 

According to CDC’s risk adjustment methodology, the SIR for the national baseline is 1.0. To interpret a hospital’s SIR, compare the SIR to 1.0, the national baseline SIR. This approach compares a hospital’s actual performance to what would have occurred if the hospital performed the same as the national baseline experience.

To learn more about the risk-adjustment method and how SIRs are calculated, see NHSN SIR guide at https://www.cdc.gov/nhsn/pdfs/ps-analysis-resources/nhsn-sir-guide.pdf.

CLABSIs are primary bloodstream infections that are associated with the presence of a central vascular catheter. A central line is a tube that is placed into a patient’s large vein, usually in the neck, chest, arm or groin. The line is used to give fluids and medication, withdraw blood, and monitor the patient’s condition. A bloodstream infection can occur when microorganisms such as bacteria and fungi enter, attach and multiply on the tubing or in fluid administered through the tubing and then enters the blood.

If you develop a central line-associated blood­stream infection, you may become ill with fevers and chills or the skin around the central line may become sore and red. CLABSIs can be prevented through proper management of the central line. It is estimated that CLABSIs cost $2.7 billion a year in the United States.  According to the federal Centers for Disease Control and Prevention (CDC), approximately 41,000 CLABSIs are still reported annually despite a 13% decrease in CLABSIs.³ Approximately 28,000 deaths occur annually as a result of CLABSIs in intensive care units.⁴

CLABSIs are monitored in many inpatient locations within the hospital. This report includes CLABSI events that occurred in adult, pediatric critical/intensive care units and neonatal intensive care units (ICUs and NICUs) in each of the 70 acute care and one specialty care hospitals in New Jersey during 2023. Wards include step-down units, mixed acuity units and specialty units (hematology/oncology). The data were verified for accuracy by each hospital.

There were more than 565,000 central-line days reported to NHSN by New Jersey acute care hospitals in 2023.  The formula below provides the Statewide observed, expected and SIR for CLABSIs:

                          Observed CLABSIs=344

                          Expected CLABSIs=562.78

                          SIR=Observed/Expected=0.61

The SIR of 0.61 indicates that CLABSIs for New Jersey were 39% fewer than expected based on the national data.  The difference is statistically significant.  This means the central-line infections in New Jersey were lower than the central-line infections seen nationally.

In the ICUs in New Jersey, the SIR is as follows:

                          Observed ICU CLABSIs=103

                          Expected ICU CLABSIs=193.35

                          SIR=Observed/Expected=0.53

The SIR of 0.53 indicates that ICU CLABSIs for New Jersey were 47% lower than expected based on the national data.  The difference is statistically significant.  Intensive Care Unit central-line infections in New Jersey were lower than ICU central-line infections seen nationally.

There are 24 acute care hospitals in New Jersey which have Neonatal Intensive Care Units (NICUs).  The SIR for NICU is as follows:

                          Observed NICU CLABSIs=12

                          Expected NICU CLABSIs=28.35

                          SIR=Observed/Expected=0.42

The SIR of 0.42 indicates that NICU CLABSIs for New Jersey were 58% fewer than expected based on the national data.  The difference is statistically significant; NICU CLABSIs in New Jersey were lower than NICU CLABSIs seen nationally.

In the Wards in New Jersey, the SIR is as follows:

                          Observed WARD CLABSIs=157

                          Expected WARD CLABSIs=239.47

                          SIR=Observed/Expected=0.66

The SIR of 0.66 indicates that Ward CLABSIs for New Jersey were 34% fewer than expected based on the national data.  The difference is statistically significant; Ward CLABSIs in New Jersey were lower than ward CLABSIs seen nationally.

Catheter-Associated Urinary Tract Infections (CAUTI) is the fifth most commonly reported healthcare-associated infection in acute care hospitals.⁹  A catheter is a drainage tube that is inserted into the bladder.  The catheter is left in place and is connected to a closed collection device.

More than 30 percent of infections in acute care hospitals are reported as CAUTIs.⁶  As with other HAIs, CAUTIs are also associated with increased morbidity, mortality, length of stay and hospital costs.  It is estimated that more than 500,000 CAUTIs occur annually in the United States.³ Inpatient hospital costs range from $862 to $1,007 per incident.² CAUTIs are also associated with more than 13,000 deaths annually.⁶

CAUTIs are monitored in many inpatient locations within the hospital. This report focuses on CAUTI events that occurred in adult critical/intensive care units (CCUs or ICUs) and medical wards in each of the 70 acute care hospitals and one specialty care hospital in New Jersey during 2023. It is important to note that the CAUTI data in this report were verified for accuracy by each hospital but were not audited.

There were over 520,000 catheter days reported to NHSN by New Jersey hospitals in 2023.  The formula below provides the Statewide observed, expected and SIR for CAUTIs:

                          Observed CAUTIs=385

                          Expected CAUTIs=620.73

                          SIR=Observed/Expected=0.62

The SIR of 0.62 indicates that CAUTIs for New Jersey were 38% lower than the expected national data.  The difference is statistically significant.  This means the catheter-associated urinary tract infections in New Jersey were lower than catheter-associated urinary tract infections seen nationally.

In the ICUs in New Jersey, the SIR is as follows:

                          Observed ICU CAUTIs=126

                          Expected ICU CAUTIs=254.17

                          SIR=Observed/Expected=0.50

The SIR of 0.50 indicates that ICU CAUTIs for New Jersey were 50% lower than the expected national data.  The difference is statistically significant indicating that the catheter-associated urinary tract infections in intensive care units in New Jersey were lower than intensive care unit catheter-associated urinary tract infections seen nationally.

In the Wards in New Jersey, the SIR is as follows:

                          Observed Ward CAUTIs=206

                          Expected Ward CAUTIs=294.84

                          SIR=Observed/Expected=0.70

The SIR of 0.70 indicates that Ward CAUTIs for New Jersey were 30% lower than the expected national data.  The difference is statistically significant; catheter-associated urinary tract infections in New Jersey hospital wards were lower than those seen in national hospital wards.

A surgical site infection (SSI) is an infection that occurs in the area of the body where the surgery took place.  The SSI can be superficial, meaning it’s on the skin.  It can also be serious and affect layers under the skin, organs and/or implants.  The infection is reported if it develops within 30-90 days of the procedure. 

Surgical site infections are the most common HAI accounting for an estimated $3.3 billion and almost 1 million inpatient days.⁸   Associated costs to treat an inpatient with a SSI are between $11,874 - $34,670 per infection.²  One article notes that more than 750,000 SSIs occur each year in the United States which results in an additional 2.5 million hospital days which leads to more than $1 billion in unnecessary costs.⁷

The surgical site infections included in this report are from 2023.  The infections reported were inpatient procedures and Deep Incisional Primary and Organ/Space SSIs that were identified during admission or readmission to the same facility.  

This year’s report includes SSI data from Coronary Artery Bypass Graft (CABG) procedures, Abdominal Hysterectomy procedures, Knee Arthroplasty procedures and Colon surgery procedures.  It is important to note that only 18 of the 70 acute care hospitals are licensed as Open-Heart Surgery hospitals and are licensed by the State to perform CABG surgery.  The surgical site infection data for 2023 were verified for accuracy by each hospital but were not audited.

More than 4,200 CABG procedures were reported in NHSN by the 18 Open Heart Surgery Hospitals in New Jersey.  The formula below provides the Statewide observed, expected and SIR for CABGs:                  

                          Observed CABG infections=23

                          Expected CABG infections=34.09

                          SIR=Observed/Expected=0.68

The SIR of 0.68 indicates that the observed CABG infections were 32% less than expected based on the national data.  The difference is statistically significant which means the CABG infections in New Jersey were lower than CABG infections seen nationally.

A total of 6981 Abdominal Hysterectomy (HYST) procedures were reported in NHSN by the hospitals in New Jersey who perform the procedure.  The formula below provides the Statewide observed, expected and SIR for abdominal hysterectomies:                      

                          Observed HYST infections=49

                          Expected HYST infections=53.48

                          SIR=Observed / Expected =0.92

The SIR of 0.92 indicates that the observed abdominal hysterectomy infections were 8% less than expected based on the national data.  The difference is not statistically significant which means the abdominal hysterectomy infections in New Jersey were similar to those seen nationally.

A total of 16,482 Knee Arthroplasty (KPRO) procedures were reported in NHSN by hospitals in New Jersey who perform the procedure.  The formula below provides the Statewide observed, the expected and the SIR for knee arthroplasties:

                          Observed KPRO infections=67

                          Expected KPRO infections=58.78

                          SIR=Observed/Expected=1.14

The SIR of 1.14 indicates that the observed knee arthroplasty infections were 14% more than expected based on the national data.  The difference is not statistically significant which means the knee arthroplasty infections in New Jersey were similar than those seen nationally.

More than 8,400 Colon (COLO) procedures were reported in NHSN by hospitals in New Jersey who performed the procedure.  The formula below provides the Statewide observed, the expected and the SIR for colon procedures:

                          Observed COLO infections=173

                          Expected COLO infections=227.46

                          SIR=Observed/Expected=0.76

The SIR of 0.76 indicates that the observed colon infections were 24% less than expected based on the national data.  The difference is statistically significant.  This means that the colon infections in New Jersey were similar than the colon infections seen nationally.

The Overall SSI SIR accounts for all surgeries that were reported in New Jersey in 2023; CABG, Abdominal Hysterectomy, Knee Arthroplasty and Colon surgeries.  There were more than 36,000 surgeries reported in NHSN by New Jersey hospitals.  The formula below provides the Statewide observed, the expected and SIR for the Overall SSIs:

                          Observed SSIs=312

                          Expected SSIs=373.81

                          SIR=Observed/Expected=0.84

The SIR of 0.84 indicates that the Overall SSIs for New Jersey were 16% fewer than expected based on the national data.  The difference is statistically significant.  This means the surgical site infections in New Jersey were lower than surgical site infections seen nationally.

In addition to displaying the “observed” and “expected” numbers of events and the SIRs, the dashboard tables include a column labeled “Hospital to National Comparison”. This column classifies the hospitals’ performances as a green downward arrow which is Lower than Expected, a gray horizontal arrow which is Similar to Expected, or a red upward arrow which is Higher than Expected. A hospital performed better than the national baseline if the Hospital to National Comparison has a green downward arrow or Lower than Expected, as indicated in the dashboard table.

In trying to determine a hospital’s performance, it is important to account for the fact that some differences occur simply due to chance. Although not shown in the table, 95% confidence intervals are used to determine how statistically certain is the conclusion that a hospital’s SIR is higher or lower than 1.0. For more details, refer to the HAI Data Tables at https://www.nj.gov/health/healthcarequality/health-care-professionals/healthcare-associated-infections/.

Please keep in mind the following before making conclusions about a hospital:

Even though hospitals reviewed and verified accuracy of the data used in this report, the data have not been audited by an independent agency.

It is also important to note that a hospital which performed lower than the national baseline, does not necessarily mean the hospital is better but that they may need to improve their HAI surveillance protocols.  Conversely, a hospital which performed higher than the national baseline is not necessarily a poor performer.  This hospital could have better infection surveillance and detection processes instituted throughout their facility.

In addition, the risk-adjustment method may not fully capture how sick patients are in certain hospitals and locations. The sicker the patients are, the more likely a hospital is to have a higher number of events. Therefore, it is important to use caution when interpreting the hospital infection data.   

References

¹ Health Care-Associated Infections | Agency for Healthcare Research and Quality accessed August 26, 2025.

² Scott, RD. The Direct Medical Costs of Healthcare-Associated Infections in U.S. Hospitals and the Benefits of Prevention. https://stacks.cdc.gov/view/cdc/11550 accessed August 28, 2025.

³ Zamel, HA. The Latest on CLABSIs and CAUTIs: Evidence-Based Approaches for Infection Prevention. Infection Control Today, February 27, 2025 https://www.infectioncontroltoday.com/view/latest-clabsis-cautis-evidence-based-approaches-infection-prevention accessed August 28, 2025.

⁴ Central Line-Associated Bloodstream Infections (CLABSI) | Agency for Healthcare Research and Quality accessed September 2, 2025.

⁵  Centers for Disease Control and Prevention, APIC, Joint Commission, IDSA, AHA, SHEA,  FAQ Sheet about “Catheter-Associated Bloodstream Infections”

⁶ Klevens RM, Edward JR, et al. Estimating health care-associated infections and deaths in U.S. hospitals, 2002. Public Health Reports 2007; 122:160-166.

⁷ Edmiston, CE, Spencer, M, Lewis, BD, et al., Reducing the Risk of Surgical Site Infections: Did We Really Think SCIP Was Going to Lead Us to the Promised Land? Surgical Infections 2011; 12(3):169-177.

⁸ Zimlichman, E., et al., Health Care-Associated Infections. A Meta-analysis of Costs and Financial Impact on the US Health Care System. JAMA Intern Med, 173(22): (2013): 2039-46.

⁹ Magill S., O’Leary S. Janelle D., et al. Changes in Prevalence of Health Care Associated Infection in the U.S. Hospitals. New England Journal of Medicine . 2018;379: 1732-1744.