A new study by researchers in St. Louis has found that altering the electronic ordering system for urinary tract infection (UTI) tests was associated with a 45% reduction in urine cultures performed at a large academic medical center.
The single-center study, published yesterday in Infection Control and Hospital Epidemiology, describes an intervention that included a change in the hospital's computerized physician order entry (CPOE) system to encourage clinicians to order a urine reflex test before ordering a urine culture. A before-and-after evaluation observed that, in addition to cutting down on unnecessary urine cultures, the intervention also reduced hospital costs by more than $100,000, without impeding the ability to detect UTIs.
The findings are noteworthy because, while UTIs are a common occurrence in hospital patients, especially in patients with catheters, unnecessary ordering of urine cultures when there's no clinical suspicion of a UTI and subsequent antibiotic treatment for asymptomatic bacteriuria—the presence of bacteria in the urine with no symptoms of infection—is also common. Antibiotic treatment provides no benefit for asymptomatic bacteriuria, however, and can contribute to antibiotic resistance.
"Ordering tests when the patient needs them is a good thing," lead study author David Warren, MD, an infectious disease specialist and professor of medicine at Washington University School of Medicine in St. Louis, said in a university press release. "But ordering tests when it's not indicated wastes resources and can subject patients to unnecessary treatment."
Fewer urine cultures performed
The staged intervention, implemented at Barnes-Jewish Hospital in St. Louis, a 1,250-bed academic hospital, involved the inclusion of a urine reflex test in commonly used order sets in the CPOE system in April 2016.
Urine reflex, or dipstick, tests can detect inflammatory cells in the urine that could indicate an infection, while urine cultures check for the presence of bacteria. The intervention also changed the ordering system so that the default setting was to order a urine reflex test followed by a urine culture, rather than a urine culture alone—although clinicians could still order isolated urine cultures.
In addition, before the changes in the CPOE were made, clinicians at the hospital received an email explaining why urine reflex tests should be ordered before a urine culture.
To evaluate the impact of this strategy, Warren and his colleagues compared urine culture rates at the hospital before the intervention (January 2015 to April 2016) and after the intervention (May 2016 to August 2017).
Overall, 18,954 inpatients had 24,569 urine cultures ordered during the study period, at a rate of 29.4 urine cultures per 1,000 patient-days, and 6,642 urine cultures (27%) were found positive. The researchers found that urine cultures decreased by 45.1% in the post-intervention period for any specimen type, falling from 38.1 per 1,000 patient-days to 20.9 per 1,000 patient-days (P < .001). They also observed significant decreases in clean-catch urine cultures (30.1 per 1,000 patient-days to 18.7, P < .001) and catheterized urine cultures (7.8 per 1,000 patient-days to 1.9, P < .001).
Despite the significant decrease in urine cultures ordered for patients with catheters, there was no significant change in the rates of catheter-associated UTIs after the intervention (0.30 per 1,000 patient days pre-intervention vs 0.30 per 1,000 patient days post-intervention, P = .871). Warren and his colleagues also observed a significant increase in the proportion of positive cultures in the post-intervention period (25.5% pre-intervention vs 29.7% post-intervention, P < .001), and a decrease in the proportion of isolated urine cultures (26.0% pre-intervention vs 24.2% post-intervention, P = .002).
The intervention resulted in a $6,490 reduction in the mean monthly laboratory cost for inpatient urine cultures, with an estimated total cost savings of $103,345.
"We were able to reduce the number of tests ordered substantially without diminishing the quality of care at all, and at a substantial cost savings," Warren said.
Limitations of the study include a retrospective design, the absence of chart review for test indication, and lack of data on antibiotic use in patients, which prevented the researchers from assessing the impact of the intervention on antibiotic treatment.
Feb 21 Infect Control Hosp Epidemiol abstract
Feb 21 Washington University School of Medicine press release