Inappropriate Treatment for Asymptomatic Bacteriuria Is Common, Risky

Inappropriate antimicrobial treatment for asymptomatic bacteriuria (ASB) is common and has been associated with longer hospital stays, a new study found, suggesting that sending urine out for testing in asymptomatic patients should be avoided.

The retrospective cohort study, published in JAMA Internal Medicine, involved 2733 patients at 46 hospitals in Michigan and aimed to evaluate a possible association between treatment of ASB, which national guidelines recommend against, and outcomes.

“We found that among almost 3000 patients treatment of ASB was very common (83%),” lead author Lindsay Ann Petty, MD, assistant professor at University of Michigan Medical School, told Contagion^®. “The strongest factor associated with treatment of ASB was an abnormal urinalysis, which likely represents a misinterpretation of the UTI diagnostic criteria. Specifically, clinicians should not presume that pyuria or nitrites in the absence of urinary symptoms is diagnostic of a UTI, and this is an important area to focus on education and stewardship interventions.”

Although the study found no benefits to treatment of ASB, the treatment was associated with a 37% increase in hospital stays.

Inappropriate use of antibiotics is associated with increased antibiotic resistance and Clostridioides difficile infection, and many antimicrobial stewardship programs have adopted strategies to reduce use, including ASB treatment. Still, high rates of antibiotic treatment persist.

“We were surprised to find that there was an increase in the duration of hospital stay associated with treatment,” Petty told Contagion^®. “One pushback we’ve heard frequently from providers arguing to send urine testing, even in the face of no urinary symptoms, is not wanting to delay care and prolong a patient’s hospital stay. We found the opposite to be true. As one of the biggest risk factors for inappropriate treatment is a positive urinalysis, not sending the urine testing if there aren’t symptoms may actually, down the road, decrease a patient’s hospital stay.”

Previous studies found that older patients and those with an altered mental state were more likely to receive treatment for ASB. This study found similar associations, along with an increased likelihood of treatment among patients with dementia and urinary incontinence.

The study found that 13.7% of patients had an indwelling urinary catheter, 41.6% had chronic kidney disease, 39.4% had diabetes, and 20.5% had dementia.

Positive urinalysis or urine culture results were a top indicator of treatment, despite a poor positive predictive value of these tests.

“We hope that antimicrobial stewardship teams will take these data and [use them] to arm their conversations with people (including MDs, DOs, APPs, RNs, patients and their families) who are hesitant to withhold treatment of ASB out of fear of potential harm,” Petty told Contagion^®.

“Additionally, we would like to look more closely, in a future study, at the patients with dementia and ASB. The elderly patient with dementia presenting with acutely altered mental status and bacteriuria is a topic of hot debate, with little data to guide clinicians, but many deeply held beliefs. The recently published IDSA [Infectious Diseases Society of America] ASB Management guidelines encourage watchful waiting in patients without systemic signs of infection. We used a similar approach in the study, and only defined a patient with AMS to be ‘asymptomatic’ if they were clinically stable without potential signs of systemic infection. We feel that this is a group that it is reasonable to assess for other causes of AMS (medication changes, dehydration, etc.) first, and avoidance of antibiotics remains critical.”

Funding for the study was provided by a grant from Blue Cross Blue Shield of Michigan.

Overuse of antibiotics is a growing concern with the emergence of antimicrobial resistance. A recent study found that clinicians have a low threshold for initiating antibiotics in patients with symptoms similar to urinary tract infections who visit the emergency department.

Another study found that male patients exposed to longer durations of antibiotic treatment for urinary tract infections received no benefits and were more likely to experience a recurrence within 1 year compared with those who received shorter treatment.