Reviewed by: James “Brad” Cutrell, MD, UT Southwestern Medical Center and Valeria Fabre, MD, Johns Hopkins University School of Medicine

Since antimicrobial stewardship in the outpatient setting is a pressing issue, two recent studies add much-needed data to better define the current landscape of outpatient antibiotic prescribing and potential target groups and geographic regions for further education and stewardship interventions in the US.

First, King and colleagues in the CDC’s Office of Antibiotic Stewardship conducted a national study of US outpatient antimicrobial prescribing between 2011 to 2016 using the IQVIA Xponent database and a proprietary method to estimate dispensing from outpatient pharmacies regardless of setting. Ratios of broad- to narrow-spectrum antibiotics were calculated, and prevalence rate ratios (pRRs) were estimated using the year 2011 as the reference. Findings: oral outpatient antibiotic use declined from a peak rate of 877 prescriptions per 1000 persons in 2011 to 836 per 1000 persons in 2016, an overall decline of 5% (pRR 0.95). However, this decline in prescribing was driven by a 13% decrease in rates of pediatric antibiotic prescribing while adult prescribing rates increased by 2%. Regionally, there were the greatest declines in the West (10%), while prescribing was highest in the South in all years and only decreased by 2% over the study period. The overall ratio of broad- to narrow-spectrum antibiotics declined from 1.62 in 2011 to 1.49 in 2016, but with greater declines seen in children. Much of this was driven by decreases in fluoroquinolone and macrolide prescribing. While family practice providers accounted for the largest percentage of antibiotics prescribed in each year, nurse practitioners and physician assistants were two groups that showed the highest increases in proportion of prescriptions written, accounting for over 25% in 2016.

Second, Staub and colleagues retrospectively analyzed 2016 outpatient retail pharmacy oral prescriptions in Tennessee. Mail-order pharmacy, federal facility pharmacy, and inpatient-healthcare-facility–pharmacy prescriptions were excluded as well as nonantibacterial and non–orally administered prescriptions. High prescribers were identified by creating a Pareto chart in which each individual prescriber’s total antibiotic prescriptions, ordered from highest to lowest, were plotted against the cumulative total statewide antibiotic prescriptions. “High prescribers” to “non–high prescribers” were compared using a multivariate logistic regression. Findings: The outpatient prescription rate was 1,195 antibiotic prescriptions per 1,000 total population. Female patients had a significantly higher antibiotic prescription rate as well as patients <2 yo or > 65 yo. Prescribers practicing in rural areas (4.7%) wrote 8.7% of prescriptions but averaged the highest prescriptions per prescriber. Of all specialties, nurse practitioners (22.9% of all prescribers) wrote the most antibiotic prescriptions (30.6%). High prescribers also prescribed more broad-spectrum antibiotics than their non–high-prescribing counterparts although they prescribed fluoroquinolones less often than non–high prescribers. Physicians born in the 1960s were most likely to be high prescribers compared to those born in the 1980s, the youngest group in this dataset. Of the state’s total antibiotic prescriptions, 50% were written by 9.3% of all prescribers. In the multivariable logistic regression, female prescribers and prescribers practicing in urban areas were associated with less likelihood of being a high prescriber.

References:

  1. King LM, et al. (2020). Changes in US Outpatient Antibiotic Prescriptions From 2011-2016. Clinical Infectious Diseases, 70(3): 370-7. https://doi.org/10.1093/cid/ciz225 
  2. Staub MB, et al. (2020). Analysis of a high-prescribing state’s 2016 outpatient antibiotic prescriptions: Implications for outpatient antimicrobial stewardship interventions. Infection Control & Hospital Epidemiology, 41: 135–142. https://doi.org/10.1017/ice.2019.315