Introducing a population-based outcome measure to evaluate the effect of interventions to reduce catheter-associated urinary tract infection

Abstract

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 might not adequately reflect all efforts aimed to enhance patient safety by reducing urinary catheter use.

Methods: We used computer-based Monte Carlo simulation to compare the NHSN-recommended CAUTI rate (CAUTIs per 1,000 catheter-days) with the proposed "population CAUTI rate" (CAUTIs per 10,000 patient-days). We simulated 100 interventions with a wide range of effects on catheter utilization and CAUTI risk in patients with catheters, and then compared the 2 measures before and after intervention across the simulated interventions.

Results: Out of our 100 simulated interventions, 93 yielded reductions in CAUTI; however, in 25 (27%) of these 93 simulations, the NHSN CAUTI rate increased after the intervention. In addition, among the 68 simulations in which both the NHSN and the population CAUTI rates decreased, the percent decreases in the population CAUTI rate were consistently greater than those in the NHSN rate.

Conclusion: The population CAUTI rate-CAUTIs per 10,000 patient-days-should be calculated along with the NHSN rate, particularly in settings where interventions lead to substantial reductions in catheter placement. We suspect that this population CAUTI rate may eventually emerge as a primary outcome for hospital-based quality improvement interventions for reducing urinary catheter utilization, especially those focusing on avoiding urinary catheter placement.

Figure 1

The structure of the simulation model

Figure 2

Percent change in population CAUTI Rate and NHSN CAUTI rate across a wide range of interventions Notes: (i) CAUTI: catheter-associated urinary tract infection; NHSN: National Healthcare Safety Network. (ii) Points A, B, and C each reflect different simulated interventions. (iii) Red areas indicate that, for interventions represented by these areas, the measure increased from pre- to post-intervention, and similarly blue areas indicate that the measure decreased (the magnitude of the increase or decrease is given by the bar in the center in terms of percent change).