Smart Prescribing Strategies Improve Antibiotic Stewardship

Heidi Splete

May 14, 2021

"Antibiotic stewardship is never easy, and sometimes it is very difficult to differentiate what is going on with a patient in the clinical setting," said Valerie M. Vaughn, MD, of the University of Utah, Salt Lake City, at SHM Converge, the annual conference of the Society of Hospital Medicine.

Dr Valerie Vaughn

"We know from studies that 20% of hospitalized patients who receive an antibiotic have an adverse drug event from that antibiotic within 30 days," said Vaughn.

Vaughn identified several practical ways in which hospitalists can reduce antibiotic overuse, including in the management of patients hospitalized with COVID-19.

Identify Asymptomatic Bacteriuria

One key area in which hospitalists can improve antibiotic stewardship is in recognizing asymptomatic bacteriuria and the harms associated with treatment, Vaughn said. For example, a common scenario for hospitalists might involve and 80-year-old woman with dementia, who can provide little in the way of history, and whose chest x-ray can't rule out an underlying infection. This patient might have a positive urine culture, but no other signs of a urinary tract infection. "We know that asymptomatic bacteriuria is very common in hospitalized patients," especially elderly women living in nursing home settings, she noted.

In cases of asymptomatic bacteriuria, data show that antibiotic treatment does not improve outcomes, and in fact may increase the risk of subsequent UTI, said Vaughn. Elderly patients also are at increased risk for developing antibiotic-related adverse events, especially Clostridioides difficile. Asymptomatic bacteriuria is any bacteria in the urine in the absence of signs or symptoms of a UTI, even if lab tests show pyuria, nitrates, and resistant bacteria. These lab results are often associated with inappropriate antibiotic use. "The laboratory tests can't distinguish between asymptomatic bacteriuria and a UTI, only the symptoms can," she emphasized.

Contain Treatment of Community-Acquired Pneumonia

Another practical point for reducing antibiotics in the hospital setting is to limit treatment of community-acquired pneumonia (CAP) to 5 days when possible. Duration matters because for many diseases, shorter durations of antibiotic treatments are just as effective as longer durations based on the latest evidence. "This is a change in dogma," from previous thinking that patients must complete a full course, and that anything less might promote antibiotic resistance, she said.

"In fact, longer antibiotic durations kill off more healthy, normal flora, select for resistant pathogens, increase the risk of C. difficile, and increase the risk of side effects," she said.

Ultimately, the right treatment duration for pneumonia depends on several factors including patient factors, disease, clinical stability, and rate of improvement. However, a good rule of thumb is that approximately 89% of CAP patients need only 5 days of antibiotics as long as they are afebrile for 48 hours and have 1 or fewer vital sign abnormalities by day 5 of treatment. "We do need to prescribe longer durations for patients with complications," she emphasized.

Revisit Need for Antibiotics at Discharge

Hospitalists also can practice antibiotic stewardship by considering four points at patient discharge, said Vaughn.

First, consider whether antibiotics can be stopped. For example, antibiotics are not needed on discharge if infection is no longer the most likely diagnosis, or if the course of antibiotics has been completed, as is often the case for patients hospitalized with CAP, she noted.

Second, if the antibiotics can't be stopped at the time of discharge, consider whether the preferred agent is being used. Third, be sure the patient is receiving the minimum duration of antibiotics, and fourth, be sure that the dose, indication, and total planned duration with start and stop dates is written in the discharge summary, said Vaughn. "This helps with communication to our outpatient providers as well as with education to the patients themselves."

Bacterial Coinfections Rare in COVID-19

Vaughn concluded the session with data from a study she conducted with colleagues on the use of empiric antibacterial therapy and community-onset bacterial coinfection in hospitalized COVID-19 patients. The study included 1,667 patients at 32 hospitals in Michigan. The number of patients treated with antibiotics varied widely among hospitals, from 30% to as much as 90%, Vaughn said.

"What we found was that more than half of hospitalized patients with COVID (57%) received empiric antibiotic therapy in the first few days of hospitalization," she said.

However, "despite all the antibiotic use, community-onset bacterial coinfections were rare," and occurred in only 3.5% of the patients, meaning that the number needed to treat with antibiotics to prevent a single case was about 20.

Predictors of community-onset co-infections in the patients included older age, more severe disease, patients coming from nursing homes, and those with lower BMI or kidney disease, said Vaughn. She and her team also found that procalcitonin's positive predictive value was 9.3%, but the negative predictive value was 98.3%, so these patients were extremely likely to have no coinfection.

Vaughn said that in her practice she might order procalcitonin when considering stopping antibiotics in a patient with COVID-19 and make a decision based on the negative predictive value, but she emphasized that she does not use it in the converse situation to rely on a positive value when deciding whether to start antibiotics in these patients.

Vaughn had no financial conflicts to disclose.

This MDedge News article originally appeared on The Hospitalist, an official publication of the Society of Hospital Medicine. MDedge is part of the Medscape Professional Network.


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