NHSN central line day methodology: impact on CLABSI rates, benchmarking, and quality improvement across a multi-hospital health system.

BACKGROUND

Under current National Healthcare and Safety Network (NHSN) methodology for CLABSI reporting, patients with multiple, concurrent central lines are counted as one line day, potentially underestimating true central line exposure.

OBJECTIVE

To evaluate the impact of NHSN central line reporting guidelines on CLABSI rates, benchmarking, and quality improvement outcomes across a multi-hospital health system.

DESIGN

Retrospective observational study.

METHODS

Electronic health record (EHR) data was collected for 7,645 inpatients across three adult acute care and one pediatric acute care hospital from January 2024 through December 2024. Additional data from the academic medical center's intensive care units (ICU) was collected from January 2025 to July 2025. Reported and actual central line days were compared across hospitals and care settings.

RESULTS

Actual line days totaled 113,529 compared to 90,789 reported line days with significantly different proportions across hospitals (P < .001). The reduction in CLABSI rate calculation when using actual line days was largest at higher-acuity settings, with the academic medical center ICUs demonstrating a decrease from 1.54 to 1.03 per 1,000 line days, a 33% reduction. Evaluation of a quality improvement initiative revealed significant improvement across all three ICUs when using actual line days, compared to only two ICUs under reported data alone.

CONCLUSIONS

Current NHSN reporting methodology systematically underestimates central line exposure at higher-acuity hospitals, impacting CLABSI benchmarking and obscuring quality improvement initiatives. Health systems should consider monitoring both reported and actual line days when evaluating performance or the impact of quality improvement initiatives.