Low-effort intervention may help cut unnecessary urine cultures

Analyzing urine samples

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A quality improvement project initiated in the country's largest safety-net hospital system was tied to significantly fewer inappropriate urine cultures, researchers reported today in the American Journal of Infection Control.

The project, which implemented changes in the electronic health record (EHR) system that prompt providers to think twice before ordering a urine culture, was associated with a more than 20% reduction in inpatient urine cultures and urine cultures from patients with urinary catheters. No additional education or stewardship was implemented.

The study authors say the intervention could provide a model for other hospitals looking for less resource-intensive ways to reduce unnecessary urine cultures.

Unnecessary cultures can lead to unneeded antibiotics

The project was implemented at 11 acute care hospitals in the New York City Health and Hospitals (NYC H+H) System, the largest municipal healthcare system in the country. The aim was to curb overdiagnosis and treatment of asymptomatic bacteriuria (ASB), a condition in which bacteria are present in a patient's urine but there are no signs or symptoms of a urinary tract infection.

Treatment of ASB with antibiotics is common in US hospitals, with some studies showing that up to 80% of patients with ASB receive antibiotics. But it has no benefit for most patients with ASB and can lead to harms, including side effects from antibiotics, longer hospitals stays, and antibiotic resistance. Guidelines from the Infectious Diseases Society of America and other organizations advise against antibiotics for ASB.

As a result, hospitals around the country have implemented antibiotic stewardship interventions aimed at reducing antibiotic prescribing for ASB. They've also looked at ways to reduce the unnecessary collection of urine cultures, which can trigger providers to prescribe antibiotics when bacteria are detected. Typically, such interventions are multifaceted and require a lot of resources.

To curb the ordering of urine cultures at NYC H+H in a less resource-intensive manner, the system's High Value Care Council made a change in the EHR in July 2021 that required providers to provide a reason for ordering a urine culture.

In October 2021, they added a best practice advisory (BPA) that appeared in the EHR when urine cultures were ordered for patients with urinary catheters who had been in the hospital for more than 48 hours. The BPA alert stated that patients with urinary catheters typically have a high rate of bacterial colonization and that most positive urine cultures in those patients may represent ASB.

To assess the effectiveness of these EHR changes, NYC H+H researchers compared the number of urine cultures ordered per 1,000 patient-days, and the number of cultures ordered per 1,000 patient-days for patients with catheters, during the pre-intervention (June 23, 2020 to October 11, 2021) and post-intervention (December 7, 2021 to August 22, 2022) periods. They also assessed the rate of catheter-associated urinary tract infections (CAUTIs) and the BPA acceptance rate.

Significant drop in urine culture orders

Urine culture orders declined in the inpatient setting from 32.68 per 1,000 patient-days pre-intervention to 25.85 per 1,000 patient-days post-intervention, a 20.9% decline. While all hospitals in the system saw a significant reduction in the number of urine cultures ordered, the declines ranged from 29.5% to 9.7%. The study authors say that wide variation calls for further research.

For patients with urinary catheters after 48 hours of hospitalization, urine culture orders fell from 2.36 per 1,000 patient-days to 1.85—a 21.6% reduction. Rates of CAUTIs were similar in the pre- and post-intervention periods (1.95 and 16.3 per catheter device-days, respectively). The BPA was triggered 4,822 times, with 552 urine culture orders removed, for an acceptance rate of 11.4%.

We believe this successful intervention can be a model for other institutions, and may be especially valuable in resource-limited, safety-net systems.

Although the study did not assess downstream impacts, such as resulting antibiotic use for ASB, the authors say the findings suggest the intervention was successful, could be replicated in other hospital systems, and may even be generalized to other hospital-associated infections, like Clostridioides difficile, and other low-value testing.

"This quality improvement initiative revealed that low-effort EHR interventions can successfully reduce unnecessary urine-culture orders to create better, more efficient care, particularly for vulnerable patient populations," lead study author Mona Krouss, MD, NYC H+H's assistant vice president of Value and Patient Safety, said in a press release from the Association for Professionals in Infection Control and Epidemiology. "We believe this successful intervention can be a model for other institutions, and may be especially valuable in resource-limited, safety-net systems."

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