BACKGROUND: Annual changes to National Healthcare Safety Network (NHSN) Patient Safety Component surveillance definitions may affect rates from year to year due to modifications in infection classifications. Central line-associated bloodstream infections (CLABSI) may be considered primary infections that are not related to infections at another site or secondary infections that are related to other infections that identify the same blood pathogen in a different clinical specimen. This study investigates the hypothesis that the observed CLABSI rates in Louisiana in 2015 were due to the exclusion of Candida species and yeasts from the catheter-associated urinary tract (CAUTI) infection definition.
METHODS: CLABSI and CAUTI cases from adult critical care units were extracted from the Louisiana NHSN Data Use Agreement Group. Rates were calculated as the number of infections divided by the number of device-days. Rates were compared from year to year for statistically significant changes. Data were analyzed in SAS version 9.3 and with the NHSN Statistics Calculator.
RESULTS: The overall CLABSI rate rose from 1.22 to 1.62 from 2014 to 2015 (p=0.003). The rate of these infections that were identified with Candida species or yeast rose from 0.27 to 0.40 (p<0.0001) from 2014 to 2015. The rate of CAUTI with secondary CLABSI decreased from 0.10 to 0.04 (p=0.016), and the overall CAUTI rate fell from 1.85 to 1.33 (p<0.0001) from 2014 to 2015. The aforementioned measures did not significantly change from 2013 to 2014.
CONCLUSIONS: Increases in CLABSI rates and commensurate decreases in CAUTI rates from 2014 to 2015 may be the result of NHSN definition updates that excluded Candida species and yeasts from the 2015 CAUTI definition. Aside from CLABSI rates, other infection measures may be affected by the definition update. These data demonstrate concomitants that may be incurred from NHSN definition updates. NHSN rates may be affected by a number of factors, including competent surveillance processionals and adherence to standardized Patient Safety Component definitions.