Introducing a Population-Based Outcome Measure to Evaluate the Effect of Interventions to Reduce Catheter-Associated Urinary Tract Infection

Background: The catheter-associated urinary tract infection (CAUTI) measure recommended by the National Healthcare Safety Network (NHSN) accounts for the risk of infection in patients with an indwelling urinary catheter, but may not adequately reflect all efforts in enhancing patient safety by reducing urinary catheter use.

Objective: To compare the NHSN-recommended CAUTI rate to a proposed population CAUTI rate for evaluating programs targeting a reduction in urinary catheter use.

Methods: We used computer-based Monte Carlo simulation to compare the NHSN-recommended CAUTI rate (CAUTI per 1,000 catheter days) to the proposed “population CAUTI rate” (CAUTI per 10,000 patient days). We simulated 100 interventions with a wide range of effects on catheter utilization and CAUTI risk among those with catheters, and then compared the two measures pre- and post-intervention across the simulated interventions.

Results: The NHSN CAUTI rate is not fully informative since it is insensitive to effects on catheter utilization. Further, the NHSN CAUTI rate can be highly misleading when used alone to assess the effect of an intervention for CAUTI reduction. A total of 93 of our 100 simulated interventions yielded reductions in CAUTI; however, in 25 (27%) of these simulations the NHSN CAUTI rate increased after the intervention.

Conclusions: The population CAUTI rate – CAUTIs per 10,000 patient-days – should also be calculated, particularly in settings where interventions lead to substantial reductions in catheter placement. We suspect this population CAUTI rate may eventually emerge as a primary outcome for hospital-based quality improvement interventions focused on reducing urinary catheter utilization.