Estimating central line-associated bloodstream infection incidence rates by sampling of denominator data: A prospective, multicenter evaluation

Background: Large-scale, prospective, evaluation of sampling for central line-associated bloodstream infection (CLABSI) denominator data was necessary prior to National Healthcare Safety Network (NHSN) implementation.

Methods: In a sample of volunteer hospitals from states in the Emerging Infections Program, prospective collection of CLABSI denominators (patient days, central line days [CLDs]) was performed in eligible locations for ≥6 and ≤12 consecutive months using the current NHSN method (daily collection) and also by a second data collector who sampled the denominator data 1 d/wk. The quality of the sampled data was evaluated and used to calculate estimated CLDs and CLABSI rates, which were compared with actual CLDs and CLABSI rates (daily counts).

Results: In total, 89 locations in 66 acute care hospitals participated. Sampled data were collected as intended 88% of the time; the quality of the data was comparable with the data collected daily. In locations with higher CLDs per month (≥75), estimated CLDs and CLABSI rates were similar to actual CLDs and CLABSI rates; however, there were significant differences in actual and estimated values among locations with lower (≤74) CLDs per month.Sampling was successfully implemented, but significant differences in the accuracy of estimated CLDs and CLABSI rates, based on the actual number of CLDs per month, were noted.

Conclusion: For locations with a higher number of CLDs per month, sampling 1 d/wk is a valid and accurate alternative to daily collection of CLABSI denominator data.