National and State Healthcare-associated Infections Standardized Infection Ratio Report
Using Data Reported to the National Healthcare Safety Network
Reporting to NHSN
Tables 1a, 1b, and 1c summarize the extent of HAI reporting to NHSN and variability in reporting of CLABSI, CAUTI, and SSI by state. In 2011, CLABSI data were reported by facilities in all 50 states, Washington, D.C., and Puerto Rico. All states had at least five facilities report CLABSI data to NHSN. As a result of the CMS Inpatient Quality Reporting Program’s requirement for reporting of CLABSI data in ICUs to NHSN, a large number of facilities began reporting CLABSI data for the first time in 2011, with 3,472 facilities reporting compared to 2,242 in 2010 (an increase of 55%). Facilities reported CLABSI data from 12,122 patient care locations in 2011 (5,722 [47%] ICU, 5,436 ward [45%], 964 [8%] NICU). CAUTI data were reported by 1,807 facilities in all 50 states, Washington, D.C., and Puerto Rico in 2011. Only three states had fewer than five facilities report CAUTI data. CAUTI reporting increased by 84% from 2010 (981 facilities reporting) to 2011. 6,402 different patient care locations reported CAUTI data to NHSN in 2011 (2,633 [41%] ICU, 3,769 [59%] ward). SSI data was reported from 2,130 facilities from 48 states and Washington, D.C. in 2011, an increase of 53% from the 1,388 facilities reporting SSI data in 2010. Seven states had fewer than five facilities report SSI data during 2011. The number of surgical procedures from the eligible categories increased by 40% from 2010 to 2011, with 748,192 procedures reported in 2011, compared to 533,269 in 2010.
National metrics summarizing the HAI experience across the United States are displayed in Table 2. The overall CLABSI SIR uses data from all patient care locations eligible for this report combined, including ICUs, wards, and NICUs (as defined in the Methods). During 2011, 18,113 CLABSIs from these locations were reported to NHSN compared to 30,616.6 CLABSIs that were predicted based on experience in the referent population. The resulting SIR of 0.592 (95% CI 0.583-0.600) translates to an approximate national reduction in the occurrence of CLABSIs from the referent period of 41%. Facility-specific SIRs were calculated for 2,335 facilities reporting sufficient denominators to predict at least one CLABSI. Half of facilities reported SIRs less than 0.469 (the median), and 90% of facilities reported SIRs less than 1.280. When tests of statistical significance were applied, 518 (22%) had an SIR that was statistically significantly less than 1.0 and 54 (2%) had an SIR statistically significantly greater than 1.0. When national SIRs were stratified by each of the three location categories, the lowest SIR was found in ICUs (SIR = 0.557), followed by wards (SIR = 0.642), and then NICUs (SIR = 0.645). All three of the location category-specific SIRs are lower than those reported in the 2010 SIR report. Four facilities only reported CLABSI data from location types that were not available during the referent period; these facilities are excluded from the analysis in Table 2.
During 2011, facilities reported 14,315 CAUTIs to NHSN from patient care locations eligible for inclusion in this report, compared to 15,398.1 predicted based on the experience in the referent population. The resulting SIR was 0.930 (95% CI 0.914-0.945), translating into a 7% reduction in CAUTIs from 2009, the referent period for CAUTI. The SIR in ICU locations (SIR 0.989, 95% CI 0.969-1.010) was not statistically significant, indicating that there has been no reduction or increase in CAUTIs in ICUs compared to the referent period. The SIR from ward locations during 2011 (SIR 0.845, 95% CI 0.823-0.868) was lower than the SIR from ICU locations, and is statistically significant, showing a reduction in CAUTIs in wards of about 15% from the referent period. Of the 1,307 facilities that reported enough data to predict at least one CAUTI during 2011, 172 (13%) had an overall CAUTI SIR significantly less than 1.0 and 133 (10%) had an overall SIR significantly greater than 1.0.
The national SSI SIR for the SCIP procedures (Appendix A) was calculated for all of the procedure categories combined as well as by individual NHSN procedure categories. For the combined national SSI SIR, 6,357 deep incisional and organ/space infections found during admission or on readmission to the same hospital were identified following 748,192 procedures. Based on the various patient and procedural risk factors reported in association with these procedures, 7,682.6 SSIs were predicted, resulting in an SIR of 0.827 (0.807, 0.848). This translates to approximately a 17% reduction in these SSIs among these procedure categories. In the facility-specific overall SSI SIR distribution, 90% of facilities reported an SIR less than 1.716, slightly improved from 2010 where the 90th percentile value was 1.813. There were 1,221 facilities with at least one predicted SSI; 141 (12%) had an SIR statistically significantly lower than 1.0 and 51 (4%) had an SIR statistically significantly greater than 1.0.
In the procedure-specific SSI SIRs, the number of facilities reporting data and the number of procedures reported varied widely among the NHSN procedure categories. Knee arthroplasty was the most commonly reported procedure, with 1,505 facilities reporting 264,155 procedures. Very little reporting was done for rectal surgery, abdominal aortic aneurysm repair, and peripheral vascular bypass surgery, with 260, 165, and 100 facilities reporting, respectively. The procedure-specific SIRs range from 0.543 to 0.896. Nine of the ten procedure-specific SIRs were significantly lower than 1.0, with vaginal hysterectomy being the lone exception (SIR 0.867, 95% CI 0.710-1.048).
State-specific CLABSI SIR data from 2011 are presented in Table 3, stratified by location category. For CLABSIs from all locations (Table 3a), SIRs for all 50 states, Washington, D.C., and Puerto Rico could be calculated: 49 of these jurisdictions had an overall CLABSI SIR that was significantly less than 1.0. All 50 states, Washington, D.C., and Puerto Rico had sufficient reporting from ICU locations to calculate CLABSI SIRs from ICUs (Table 3b): 47 of these jurisdictions had a CLABSI SIR from ICUs that was significantly less than 1.0. Fewer data were available from wards (Table 3c) and NICUs (Table 3d). SIRs that were significantly less than 1.0 were reported from wards in 30 states and NICUs in 28 states. Overall and location-specific CLABSI SIRs and their 95% CIs (by state) are summarized in Table 4.
State Specific Progress in CLABSI Prevention
Serial SIRs for states with sufficient data to produce an overall CLABSI SIR in both 2010 and 2011 are presented in Table 5. Four of the 52 reporting jurisdictions did not have sufficient data to report serial CLABSI SIRs. Of the remaining 48 jurisdictions, 30 had no change in the CLABSI SIR from 2010 to 2011 and 18 reported a decrease in CLABSI SIR from 2010 to 2011. Of these 18 jurisdictions, 15 retained a significant decrease in CLABSI SIR when the analysis was restricted to continuously reporting facilities. No jurisdictions reported an increase in CLABSI SIR between the two reporting periods when assessing data from all reporting facilities. One state with no change in CLABSI SIR in all reporting facilities from 2010 to 2011 had an increasing CLABSI SIR in continuously reporting facilities.
National Progress in CLABSI Prevention
Table 6 presents serial SIRs for national CLABSI, CAUTI, and SSI data for 2011 compared to 2010. For CLABSI, the SIR significantly decreased for the combined all-location metric, as well as each of the three location category-specific SIRs (ICUs, wards, and NICUs) in all reporting facilities; each of these decreases was confirmed in continuously reporting facilities. There was no significant change in the overall CAUTI SIR for all reporting facilities between 2010 and 2011, but when the analysis was restricted to facilities who had reported in both 2010 and 2011, there was a significant decrease in the overall CAUTI SIR. For location-specific SIRs, there was a significant decrease in the SIR among ward locations, but no change for critical care locations. These findings persisted when restricting to continuously reporting facilities. SIRs were significantly lower in 2011 compared to 2010 for the combined SSI SIR and for five of the procedure-specific SIRs. However, when only continuously reporting facilities were assessed, these decreases persisted only for the combined SSI SIR and knee arthroplasties.
Estimated Burden of Disease and Attributable Reimbursement in 2011
In 2011, the total number of critical care patient-days was estimated at 21.9 million (95% CI, 20.3-23.5 million), with an estimated 12,400 CLABSIs (95% CI, 11,500-13,300) occurring among critical care patients. The total number of superficial incisional, deep incisional, and organ/space SSIs that occurred among the estimated 3,011,412 (95% CI: 2,745,643-3,277,181) major (i.e. SCIP) surgical procedures in 2011 was 52,567 (45,332-60,844).
The attributable reimbursement (adjusted to 2011 dollars using the Employment Cost Index for all civilian employees working in hospitals) by CMS to hospitals per CLABSI was estimated to be $26,109 (95% CI, $22,885 - $29,330). Attributable reimbursement was not calculated for SSIs.