One Third of Outpatient Antibiotic Rxs May Be Inappropriate

Diana Swift

May 03, 2016

With antibiotic overuse driving the rise of antibiotic-resistant infections, authors of a large study find that during 2010 to 2011, antibiotics were prescribed for outpatients across all conditions at a rate of 506 per 1000 population. Only an estimated 353 of these, however, were likely appropriate, suggesting that 30% of these antibiotics may have been unnecessary.

These findings, published in the May 3 issue of JAMA, highlight the need to set a new goal for antibiotic stewardship in the ambulatory setting, according to Katherine E. Fleming-Dutra, MD, a pediatrician with the Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia, and colleagues.

Although the National Action Plan for Combating Antibiotic-Resistant Bacteria aims to halve the rate of inappropriate outpatient antibiotic use by 2020, figures on the actual extent of misuse have been lacking. The new study aimed to fill this gap by estimating the rates of outpatient oral antibiotic prescribing by age and diagnosis and the proportion that may be inappropriate in US adults and children.

The authors analyzed 2010 to 2011 data from the National Ambulatory Medical Care Survey and National Hospital Ambulatory Medical Care Survey.

Of the 184,032 sampled physician visits, 12.6% (95% confidence interval [CI], 12.0% - 13.3%) generated antibiotic prescriptions; most frequently, per 1000 population, antibiotics were prescribed for sinusitis (56 prescriptions; 95% CI, 48 - 64 prescriptions), suppurative otitis media (47 prescriptions; 95% CI, 41 - 54 prescriptions), and pharyngitis (43 prescriptions; 95% CI, 38 - 49 prescriptions).

Per 1000 population, acute respiratory conditions led to 221 antibiotic prescriptions (95% CI, 198 - 245 prescriptions) annually, but just 111 (50%) of these estimated to be appropriate. In addition, of the estimated 506 antibiotic scripts (95% CI, 458 - 554 prescriptions) per 1000 population written annually for any cause, only 353 (70%) were thought to be justified.

"Half of antibiotic prescriptions for acute respiratory conditions may have been unnecessary, representing 34 million antibiotic prescriptions annually," the authors write. "Collectively, across all conditions, an estimated 30% of outpatient, oral antibiotic prescriptions may have been inappropriate. Therefore, a 15% reduction in overall antibiotic use would be necessary to meet the White House National Action Plan for Combating Antibiotic-Resistant Bacteria goal of reducing inappropriate antibiotic use in the outpatient setting by 50% by 2020."

For pharyngitis specifically, the researchers estimate that 72.4% (95% CI, 66.8% - 77.4%) of cases of pharyngitis in adults and 56.2% (95% CI, 49.8% - 62.4%) in children were treated with antibiotics, even though most sore throat cases are not streptococcus A-related. In recent literature, only 37% of children with sore throat tested positive for this pathogen.

Regionally, prescribing rates ranged annually from 423 (95% CI, 343 - 504) in the West to 553 (95% CI, 459 - 648) in the South.

The data are similar to those reported in other countries. For example, in 2015, a Dutch study reported that almost half of antibiotic prescriptions written by general practitioners for respiratory tract indications failed to comply with clinical guidelines.

The CDC investigators also found that estimated appropriate prescription rates per 1000 participants varied by age group. By age, the rate was highest in children ages 0 through 2 years, at 1287 (95% CI, 1085 - 1489) antibiotic prescriptions per 1000 population. For sinusitis, they were 59 (95% CI, 32 - 86) for ages 0 through 19 years, 27 (95% CI, 17 - 36) for ages 20 through 64 years, and 37 (95% CI, 16 - 59) for age 65 years and older. For suppurative otitis media, estimated rates were 138 (95% CI, 96 - 179) for ages 0 through 19 years and 6 (95% CI, 4 - 9) for ages 20 through 64 years.

"This estimate of inappropriate outpatient antibiotic prescriptions can be used to inform antibiotic stewardship programs in ambulatory care by public health and health care delivery systems in the next 5 years," Dr Fleming-Dutra and colleagues write.

Commenting in an accompanying editorial, Pranita D. Tamma, MD, MHS, and Sara E. Cosgrove, MD, from the Johns Hopkins University School of Medicine in Baltimore, Maryland, said the study's estimates, although probably too conservative, shed important light on outpatient prescribing practices and "provide critical baseline data upon which future improvement efforts can be built." They note that although most antibiotics are prescribed in the ambulatory setting, stewardship efforts have not had much success there.

Yet research has shown that a measure as simple as a waiting room poster stating a commitment to avoid inappropriate antibiotic prescriptions for acute respiratory tract infections can result in a 20% decrease in antibiotic scripts.

Other approaches include clinician-documented justifications for antibiotics, peer-to-peer prescribing comparisons, and clinician education with personalized audit and feedback. Rapid point-of-care diagnostic tests might also help.

The commentators note that improvements will require efforts on two fronts: changing clinician behavior to ease their concerns about "diagnostic uncertainty, alienating patients, and not conforming to peer practices," and providing patient education on antibiotics. A 2015 study found that better physician–parent communication reduced pediatric antibiotic prescribing.

"Future work needs to focus on interventions targeting both clinicians and patients to help reach the national goal," Dr Tamma and Dr Cosgrove write. "It will be critical to continue to evaluate progress in improving antibiotic use in conjunction with widespread adoption of antibiotic stewardship activities in the outpatient setting."

This project was made possible through a partnership with the Centers for Disease Control and Prevention Foundation. Support for this project was provided by Pew Charitable Trusts. The authors have disclosed no relevant financial relationships. Dr Cosgrove reports serving as a consultant for Novartis and that her institution received Pfizer Grants for Learning and Change/The Joint Commission. Dr Tamma reports that her institution received Pfizer Grants for Learning and Change/The Joint Commission and grants from Merck.

JAMA. 2016;315:1839-1841, 1864-1873.

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