A new study by researchers with the Centers for Disease Control and Prevention (CDC) shows that despite a decrease in overall antibiotic use, most US adults hospitalized with COVID-19 continued to receive antibiotics beyond the first year of the pandemic.
The findings, published late last week in Open Forum Infectious Diseases, show that antibiotic use in non-critically ill patients with COVID-19 was highest in 2020 and declined thereafter. However, even in 2022, nearly two-thirds of non-critically ill patients were treated with antibiotics, and most of them received an antibiotic as soon as they were admitted to the hospital.
Infections and colonization
Using data from a hospital-based, all-payer database representing roughly 20% of all US hospitals, researchers with the CDC's Division of Healthcare Quality Promotion calculated the monthly proportion of hospital discharges in which patients received at least one antibiotic during their hospital stay, stratified by critical care status, from March 2020 to June 2022. Critically ill patients were defined as those admitted to an intensive care unit or who received invasive mechanical ventilation.
Over the study period, 1,142,752 US adults were hospitalized and discharged with a COVID-19 diagnosis at 711 hospitals, and 69.9% received an antibiotic during their hospital stay, with 88.1% receiving an antibiotic on admission. Patients who received antibiotics were more likely to be older, critically ill, have longer hospital stays, and higher in-hospital mortality. Antibiotic use was significantly higher in critically ill patients than non-critically ill patients (903 days of therapy [DOT] per 1,000 patient days [PD] vs 763 DOT/1,000 PD).
Among non-critically ill COVID-19 patients, 71.1% received an antibiotic in 2020, 92.3% of which were started on admission. Antibiotic use in non-critically ill patients fell to 61.5% in 2021 and 62.1% in 2022, and median days of therapy also significantly declined, falling by 263 DOT/1,000 PD from 2020 to 2022.
This analysis shows that despite decreases in total antibiotic use, the majority of patients hospitalized with COVID-19 continued to receive antibiotics on admission, regardless of clinical severity.
But the proportion of COVID-19 patients who received antibiotics on admission did not substantially decline. Among non-critically ill COVID patients who received antibiotics in the hospital in 2021 and 2022, 89.7% and 88.2%, respectively, received them on admission.
Ceftriaxone was the most commonly used antibiotic, frequently in combination with azithromycin, which was thought in the early months of the pandemic to potentially lessen COVID-19 severity. Use of both antibiotics declined significantly over the study period, particularly azithromycin, after several studies found it had no effect.
But the study authors also note that while National Institutes of Health COVID-19 treatment guidelines say that empiric antibiotics can be administered if bacterial pneumonia is suspected, they observed increases in other antibiotics not recommended as first-line therapy for bacterial pneumonia. Vancomycin, cefepime, and piperacillin-tazobactam were among the antibiotics that saw increases.
Opportunities for stewardship
High antibiotic use in COVID patients during the first year of the pandemic is not surprising. Several studies in the United States and other countries have reported that antibiotics were commonly used to treat COVID-19 patients, especially during the early months of the pandemic, when hospitals were overrun with patients with pneumonia-like illness and diagnostic tests and treatments were limited. Even after it was established that COVID-19 was caused by a virus and patients could be quickly diagnosed, clinicians remained concerned about the potential for bacterial co-infections.
While their study and others show that antibiotic use in COVID patients has subsequently declined, the authors say their findings suggest it still remains a problem, and that opportunities for antibiotic stewardship programs to further drive down antibiotic use in non-critically ill patients remain, particularly on admission.
"This analysis shows that despite decreases in total antibiotic use, the majority of patients hospitalized with COVID-19 continued to receive antibiotics on admission, regardless of clinical severity," they wrote. "Antibiotic stewardship interventions that improve the diagnosis and treatment of community-onset respiratory tract infections may reduce unnecessary antibiotic use and as a result, improve quality of care and patient outcomes."
