Antibiotic Prescribing for Adults With Acute Bronchitis in the United States, 1996-2010

Acute bronchitis is a cough-predominant acute respiratory illness of less than 3 weeks’ duration. For more than 40 years, trials have shown that antibiotics are not effective for acute bronchitis.¹ Despite this, between 1980 and 1999, the rate of antibiotic prescribing for acute bronchitis was between 60% and 80% in the United States.² During the past 15 years, the Centers for Disease Control and Prevention (CDC) has led efforts to decrease antibiotic prescribing for acute bronchitis.^3,4 Since 2005, a Healthcare Effectiveness Data and Information Set (HEDIS) measure has stated that the antibiotic prescribing rate for acute bronchitis should be zero.⁵

To estimate the association with ongoing CDC efforts and the implementation of the HEDIS measure, we evaluated the change in antibiotic prescribing rates for acute bronchitis in the United States between 1996 and 2010.

The National Ambulatory Medical Care Survey and National Hospital Ambulatory Medical Care Survey (NAMCS/NHAMCS) are annual, nationally representative, multistage probability surveys of ambulatory care in the United States.⁶ The NAMCS/NHAMCS collect information about physicians, outpatient practices, and emergency departments (EDs), as well as visit-level data including patient demographics, reasons for visits, diagnoses, and medications. Physicians, office staff, and US Census Bureau representatives collect information (including information about patient race/ethnicity to enable assessment of health care disparities) on visit record forms. Each visit in the NAMCS/NHAMCS is weighted to allow extrapolation to national estimates. The National Center for Health Statistics institutional review board approved the protocols for the NAMCS/NHAMCS, including a waiver of the requirement for patient informed consent.

We strove to include visits that would be eligible for the HEDIS measure.⁵ We included NAMCS/NHAMCS new problem visits made by adults aged 18 to 64 years to primary care physicians, general medicine clinics, or EDs from 1996 to 2010 with any diagnosis of acute bronchitis (International Classification of Diseases, Ninth Revision, code 466.0). We excluded patients who were admitted to the hospital or visits associated with chronic pulmonary disease, immunodeficiency, cancer, or concomitant infectious diagnoses. We classified antibiotics, the main outcome, as either extended macrolides or other.

We calculated standard errors for all results using logistic regression and the survey package in R (version 3.0.1, R Project for Statistical Computing). We considered 2-sided P values less than .05 as significant. To increase reliability, we combined data into 3-year periods.

There were 3153 sampled acute bronchitis visits meeting our inclusion and exclusion criteria between 1996 and 2010. The overall antibiotic prescription rate was 71% (95% CI, 66%-76%) and increased between 1996 and 2010 (adjusted odds ratio per 10-year period, 1.75 [95% CI, 1.06-2.90]; P = .03) (Table). There was a statistically significant increase in antibiotic prescribing in EDs (Figure). Physicians prescribed extended macrolides at 36% (95% CI, 32%-41%) of acute bronchitis visits and extended macrolide prescribing increased from 25% of visits in 1996-1998 to 41% in 2008-2010 (P = .01). Other antibiotics were prescribed at 35% (95% CI, 30%-39%) of visits, and most commonly were fluoroquinolones, aminopenicillins, and cephalosporins. The antibiotic prescribing rate for other antibiotics did not change significantly over time (48% of visits in 1996-1998 to 35% of visits in 2008-2010; P = .55).

Despite clear evidence, guidelines, quality measures, and more than 15 years of educational efforts stating that the antibiotic prescribing rate should be zero, the antibiotic prescribing rate for acute bronchitis was 71% and increased during the study period. Physicians continue to prescribe expensive, broad-spectrum antibiotics.

Our analysis has limitations. First, the sample size for some estimates was small. Second, the surveys do not capture care provided outside of clinic visits. Third, the surveys capture limited clinical information, restricting our ability to identify exclusionary factors. Fourth, as an analysis of visits, an individual patient could theoretically be included more than once, although this is unlikely given the sampling design.

Avoidance of antibiotic overuse for acute bronchitis should be a cornerstone of quality health care. Antibiotic overuse for acute bronchitis is straightforward to measure. Physicians, health systems, payers, and patients should collaborate to create more accountability and decrease antibiotic overuse.

Corresponding Author: Jeffrey A. Linder, MD, MPH, Brigham and Women’s Hospital, 1620 Tremont St, Boston, MA 02120 (jlinder@partners.org).

Author Contributions: Dr Barnett had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Study concept and design: All authors.

Acquisition, analysis, or interpretation of data: All authors.

Drafting of the manuscript: All authors.

Critical revision of the manuscript for important intellectual content: All authors.

Statistical analysis: All authors.

Obtained funding: Linder.

Administrative, technical, or material support: All authors.

Study supervision: Linder.

Conflict of Interest Disclosures: The authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Barnett reported serving as a medical advisor to Ginger.io, which has no relationship to this research. No other disclosures were reported.

Funding/Support: Dr Linder’s work on acute respiratory tract infections was supported by grant RC4 AG039115 from the National Institutes of Health, grant R21 AI097759 from the National Institute of Allergy and Infectious Diseases, and grant R18 HS018419 from the Agency for Healthcare Research and Quality.

Role of the Sponsor: The National Institutes of Health, National Institute of Allergy and Infectious Diseases, and Agency for Healthcare Research and Quality had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

Previous Presentations: Presented in part at the Society of General Internal Medicine Annual Meeting; April 25, 2013; Denver, Colorado; and at IDWeek; October 4, 2013; San Francisco, California.