Table 3.

Changes in National Healthcare-Associated Infection (HAI) Standardized Infection Ratios (SIRs) Between 2021 Quarter 3 (2021-Q3) and 2019 Quarter 3 (2019-Q3)

HAI Type	No. of Hospitals a	% Change in SIR b	95% CI	Preliminary 2021-Q3				2019-Q3
				No. of HAIs Reported	No. of HAIs Predicted	Device/Patient Days or Procedures c	SIR	No. of HAIs Reported	No. of HAIs Predicted	Device/Patient Days or Procedures c	SIR
CLABSI e	3,215	48.4 d	(41.6 to 55.5)	4,741	4,573.59	4,539,805	1.037	2,761	3,951.77	3,911,645	0.699
CAUTI f	3,208	13.6 d	(8.4 to 19.1)	4,074	5,087.85	4,325,035	0.801	2,997	4,251.81	3,592,706	0.705
VAE g	1,343	60.2 d	(54.8 to 65.8)	11,353	7,097.22	1,036,989	1.600	4,553	4,559.15	639,187	0.999
SSI, colon surgery h	2,593	−9.2 d	(−15.2 to −2.8)	1,542	1,936.21	73,976	0.796	1,774	2,021.71	79,396	0.877
SSI, abdominal hysterectomy h	2,283	−4.1	(−15.5 to 8.7)	428	410.90	58,550	1.042	559	514.35	78,020	1.087
LabID MRSA bacteremia i	3,272	45.1 d	(37.0 to 53.6)	3,066	2,625.60	40,987,396	1.168	1,927	2,393.81	37,865,802	0.805
LabID CDI j	3,269	−14.5 d	(−16.7 to −12.2)	10,565	21,905.36	37,822,902	0.482	12,408	21,999.91	34,586,039	0.564

Note. HAI, healthcare-associated infection; CI, confidence interval; CLABSI, central–line–associated bloodstream infection; CAUTI, catheter-associated urinary tract infection; VAE, ventilator-associated event; SSI, surgical site infection; LabID, laboratory-identified; MRSA, methicillin-resistant Staphylococcus aureus; CDI, Clostridioides difficile infection; CMS, Centers for Medicare and Medicaid Services; ICU, intensive care unit; NHSN, National Healthcare Safety Network. Data as of January 1, 2022.

^a The number of acute-care hospitals that reported complete HAI surveillance data for both quarters in the comparison and for the same location when applicable. SSI hospital counts represent those hospitals that reported procedure-level data eligible for inclusion in the adult Complex Admission-Readmission models used for SSI SIR calculations. Hospitals that performed zero procedures, or had zero procedures included in the SIR calculation, were excluded from the SSI hospital counts.

^b % change was calculated as follows: [(2021 SIR/2019 SIR) − 1)] × 100. This formula is equivalent to [(2021 SIR − 2019 SIR) ÷ 2019 SIR] × 100. This value is reported regardless of statistical significance, and a non-significant value should be interpreted as no statistical difference between the 2021 and 2019 SIRs.

^c Device days are shown for CLABSI, CAUTI, and VAE. Procedure counts are shown for SSI. Patient days are shown for LabID events.

^d Statistically significant result, as indicated by 2-tailed P ≤ 0.05 and the 95% CI not including zero.

^e CLABSI SIRs were calculated using data from adult and pediatric ICUs, neonatal ICUs, and adult and pediatric medical, surgical, and medical–surgical wards.

^f CAUTI SIRs were calculated using data from adult and pediatric ICUs, and adult and pediatric medical, surgical, and medical–surgical wards.

^g VAE SIRs were calculated using data from adult ICUs and wards.

^h SSIs included were those classified as deep incisional or organ-space infections following adult inpatient procedures and were detected during the same admission as the surgical procedure or upon readmission to the same hospital. The NHSN Complex Admission–Readmission model was used for SIR calculations.

ⁱ MRSA bacteremia SIRs were calculated using data from all inpatient locations in the hospital (facility-wide inpatient, or FacWideIN) except inpatient rehabilitation and inpatient psychiatric units certified by the CMS. The number of reported and predicted HAIs were limited to hospital-onset events.

^j CDI SIRs were calculated using data from all inpatient locations in the hospital (FacWideIN) except neonatal ICUs, newborn nurseries, and inpatient rehabilitation and inpatient psychiatric units certified by the CMS. The number of reported and predicted HAIs were limited to hospital-onset incident events.