METHODS: Changes in NHSN reporting protocols and analysis methods were reviewed. Patients with ED and inpatient MRSA events on the same day were matched to quantify the number of ED specimens contributing to the facility-wide inpatient CO-rate prior to 2015.
RESULTS: In Tennessee, hospitals have always been required to report MRSA LabID events from EDs. Until January 2015, facilities were instructed to enter specimens collected in EDs for patients subsequently admitted to an inpatient location on the same day as two LabID events: one for the ED, and a second for the inpatient location. These inpatient events contributed to the CO-MRSA rate which is used for risk adjustment for the SIR. Due to changes in the LabID event surveillance protocol, these events no longer contribute to the CO-MRSA rate.
Prior to 2015, about 50% of ED MRSA LabID events matched to an inpatient LabID event on the same day (36% of all CO events). The 2015 protocol change, which excludes these ED events from the facility-wide inpatient CO rate, was likely the most significant contributor to the 25% decrease in Tennessee’s CO rate observed between 2014 and 2015 resulting in the 27% increase in SIR.
CONCLUSIONS: CDC implemented significant changes to the NHSN reporting protocol in 2015, in advance of calculating new national baseline data. While this new baseline will improve risk adjustment, facilities are currently using rates and SIRs from NHSN based on old risk adjustment methods to drive their prevention activities. It is important to quantify the impact protocol changes have on NHSN data, to inform stakeholders who use these data for prevention. The impact of the protocol change may be more pronounced in Tennessee than other states, due to the training Tennessee facilities received on NHSN reporting and Tennessee’s ED requirement prior to 2015.