By Seema Gupta, MD, MSPH

Clinical Assistant Professor, Department of Family and Community Health, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV

Dr. Gupta reports no financial relationships relevant to this field of study.

SYNOPSIS: In a retrospective cohort study of outpatient visits for upper respiratory infections that should not require antibiotics, researchers found several patient, practice, and provider characteristics associated with inappropriate antimicrobial prescribing. Notably, adult patients seen by an advanced practice provider were 15% more likely to receive an antimicrobial than those seen by a physician provider.

SOURCE: Schmidt ML, Spencer MD, Davidson LE. Patient, provider, and practice characteristics associated with inappropriate antimicrobial prescribing in ambulatory practices. Infect Control Hosp Epidemiol 2018;39:307-315.

According to the CDC, antimicrobial resistance is one of the most serious contemporary public health challenges in the United States. While antibiotics have transformed our ability to treat infections, at least 2 million people become infected with bacteria that are resistant to antibiotics each year, resulting in more than 23,000 deaths annually in the United States.1 In particular, antibiotic resistance in children and older adults is of significant concern, as these age groups use more antibiotics than any other age group. It is estimated that at least 30% of the antibiotic prescriptions provided in the outpatient setting are unnecessary and the overall total inappropriate antibiotic use may approach 50% of all outpatient antibiotic use.2 Most of this unnecessary use is for acute respiratory conditions, such as upper respiratory tract infections, bronchitis, sore throats caused by viruses, and even some sinus and ear infections. Additionally, antibiotic use also carries negative implications, causing one out of five ED visits for adverse drug events.3 While the overuse of antibiotics is a clearly modifiable cause of increases in drug-resistant bacteria, the approach to antibiotic prescribing in United States outpatient settings is highly variable. Increasingly, antimicrobial stewardship is included in various clinical practice guidelines to achieve appropriate antibiotic prescribing. However, it is equally critical that we understand the various characteristics that influence prescribing rates across different environments, providers, and patients, as this will help bring about more rapid transformation in strategies for effective antimicrobial stewardship, resulting in improved patient care.

In their retrospective cohort study, Schmidt et al collected data from outpatient visits that occurred between January 2014 and May 2016 from the Carolinas HealthCare System. These visits were for common respiratory conditions that should not require antimicrobials (acute bronchitis, bronchiolitis, nonsuppurative otitis media, or viral upper respiratory infection). The cohort included 448,990 visits involving 281,315 unique patients seen across 246 practices and 898 providers at urgent care, family medicine, internal medicine, and pediatric practices.

Researchers found that overall prescribing rates for both adult and pediatric patients were 407 per 1,000 visits (95% confidence interval [CI], 405-408). Of the four conditions, acute bronchitis carried the highest rate of inappropriate prescription at 703 per 1,000 visits (95% CI, 700-706) in the unadjusted analysis. After adjustment, adult patients seen by an advanced practice provider were 15% more likely to receive an antimicrobial than those seen by a physician provider (incident risk ratio [IRR], 1.15; 95% CI, 1.03-1.29). In the pediatric sample, older providers (51-60 years of age) were four times more likely to prescribe an antimicrobial than providers aged ≤ 30 years (IRR, 4.21; 95% CI, 2.96-5.97). Family medicine practices demonstrated the highest rate of prescribing, while pediatric practices exhibited the lowest. Researchers also found that as patient age increased, the likelihood of receiving an antimicrobial for any of the four indications also rose up to age 64 years, after which the likelihood declined, with IRRs increasing by age category in both adult and pediatric models. For adults seen in a metropolitan area, the risk of receiving an antibiotic was 36% greater than those seen in rural practices. Finally, white patients were more likely than other races to receive antibiotics, and those with Medicaid, Medicare, or other payment methods were less likely to receive an antimicrobial compared to patients with managed care plans.


While significant success in antimicrobial stewardship in the acute inpatient care setting has been demonstrated over the past two decades, leading to a decrease in inappropriate antibiotic use and decreasing antimicrobial resistance, most antibiotic use occurs in outpatient settings, which makes it a critical target of antimicrobial stewardship. Understanding the characteristics that are most significantly associated with inappropriate antibiotic prescribing in outpatient setting in which the population varies widely in acuity, microbiologic etiology, and patient presentation is central to achieving a similar success. Although changing prescribing behaviors can be difficult, there are clear, proven, evidence-based methods to optimize antibiotic therapy for individuals while minimizing harm to the patient and reducing antibiotic resistance in the community. Schmidt et al provided evidence that future stewardship efforts, recommendations, and interventions can be tailored to specific settings of care, provider types, and patient characteristics, which could be more effective in improving appropriate prescribing and ultimately reducing antibiotic resistance.


  1. Fleming-Dutra KE, Hersh AL, Shapiro DJ, et al. Prevalence of inappropriate antibiotic prescriptions among US ambulatory care visits, 2010-2011. JAMA 2016;315:1864-1873.
  2. Centers for Disease Control and Prevention (CDC). Office-related antibiotic prescribing for persons aged ≤ 14 years — United States, 1993-1994 to 2007-2008. MMWR Morb Mortal Wkly Rep 2011;60:1153-1156.
  3. Bourgeois FT, Mandl KD, Valim C, Shannon MW. Pediatric adverse drug events in the outpatient setting: An 11-year national analysis. Pediatrics 2009;124:e744-e750.