antibiotic therapy

Trends in Outpatient Antibiotic Prescriptions: Less Is More

Jessica Tomaszewski, MD

King LM, Bartoces M, Fleming-Dutra KE, Roberts RM, Hicks LA. Changes in US outpatient antibiotic prescriptions from 2011-2016 [published online March 16, 2019]. Clin Infect Dis.

In the age of antibiotic resistance and antibiotic-related adverse events, antibiotic stewardship is an essential part of medical care. The US government’s National Action Plan for Combating Antibiotic-Resistant Bacteria set a goal of decreasing inappropriate antibiotic use in half by 2020,1 which translates to reducing overall outpatient use by 15% compared with 2011 levels. The outpatient setting is an important stewardship target, because it is where most US antibiotic prescriptions are written.

With this goal in mind, the Centers for Disease Control and Prevention published a fascinating study describing trends in US oral antibiotic prescriptions from 2011 to 2016 using pharmacy dispensing data. This investigation looked at prescriptions by year, region, patient age group and sex, antibiotic category, and provider specialty. It also looked at the ratio of broad- and narrow-spectrum antibiotic prescriptions.

King and colleagues estimated annual oral antibiotic prescription rates using national prescription dispensing count data from the IQVIA Xponent database divided by census estimates. Provider specialties were categorized into 17 groups based on American Medical Association self-designated practice specialties, other than nurse practitioners (NPs) and physician assistants (PAs), who were categorized as such. Poisson regression models and linear regression models were used to estimate prevalence rate ratios comparing 2011 and 2016 antibiotic prescription rates and temporal trends, respectively.

During the study period, oral prescription rates decreased 5% from 877 prescriptions per 1000 persons in 2011 to 836 per 1000 persons in 2016 (prevalence rate ratio [pRR], 0.95; 95% CI, 0.95-0.95). Rates of prescriptions dispensed to children (<20 years) decreased 13% (pRR, 0.87; 95% CI, 0.87-0.87), while adult (≥20) rates increased by 2% (pRR, 1.02; 95% CI, 1.02-1.02). In all years, adults aged 40 to 64 years received the highest proportion of antibiotic prescriptions. The age group with the greatest decrease in prescription rate was the 0- to 2-year age group (-17%; pRR, 0.83; 95% CI, 0.82-0.83).

The ratio of prescribed broad- to narrow-spectrum antibiotics decreased from 1.62 in 2011 to 1.49 in 2016, most notably by decreases in prescriptions for macrolides and fluoroquinolones. This trend was noted in all age groups, but the ratio throughout the study period was higher in adults, suggesting a higher proportion of broad-spectrum antibiotic prescriptions in adults.

Family practice physicians prescribed the highest proportion of antibiotics in all years. Of note, the prescriptions written by NPs and PAs increased from 2011 to 2016 such that these providers prescribed more than 25% of all antibiotic prescriptions in 2016.

There were limitations on the data gathered from this study. The patients’ diagnoses and specific allergies were unknown to the researchers, limiting a more nuanced exploration of antibiotic selection.

Outpatient antibiotic prescription rates have decreased, solely driven in decreases in the pediatric population. This is likely multifactorial in cause, including the introduction of the more-robust pneumococcal vaccine and stricter diagnostic criteria for otitis media, among other factors. Adult practitioners, including NPs and PAs, are important targets for further education regarding antibiotic stewardship.


  1. U.S. National Action Plan for Combating Antibiotic-Resistant Bacteria (National Action Plan). Centers for Disease Control and Prevention. Published March 2015. Accessed May 6, 2019.