CONTEXT: The impact of national efforts to limit antibiotic prescribing has not been fully evaluated.
OBJECTIVES: To analyze trends in outpatient visits associated with antibiotic prescription for U.S. adults.
DESIGN: Cross-sectional study of data (1995 to 2002) from the National Ambulatory Medical Care Survey and the National Hospital Ambulatory
Medical Care Survey.
PARTICIPANTS: Adults ≥18 years with an outpatient visit to an office-or hospital-based medical practice or to an emergency department.
All visits were classified into 1 of 4 diagnostic categories: (1) acute respiratory infection (ARI)—antibiotics rarely indicated,
(2) ARI—antibiotics often indicated, (3) nonrespiratory infection—antibiotics often indicated, and (4) all others.
MEASUREMENTS: Trends in: (1) Proportion of outpatient visits associated with an antibiotic prescription; (2) proportion of antibiotic prescriptions
that were broad spectrum; and (3) number of visits and antibiotic prescriptions per 1,000 U.S. adults ≥18 years of age.
RESULTS: From 1995–1996 to 2001–2002, the proportion of all outpatient visits that generated an antibiotic prescription decreased
from 17.9% to 15.3% (adjusted odds ratio [OR] 0.84, 95% confidence interval [CI] 0.76 to 0.92). The entire reduction was because
of a decrease in antibiotic prescriptions associated with visits for ARIs where antibiotics are rarely indicated from 59.9%
to 49.1% (adjusted OR 0.64 95% CI 0.51 to 0.80). However, the proportion of prescribed antibiotics for these visits that were
classified as broad-spectrum antibiotic prescription increased from 41.0% to 76.8%. Overall outpatient visits increased from
1693 to 1986 per 1,000 adults over the 8 years studied, but associated antibiotic prescriptions changed little, from 302 to
304 per 1,000 adults.
CONCLUSION: During the study period, outpatient antibiotic prescribing for respiratory infections where antibiotics are rarely indicated
has declined, while the proportion of broad-spectrum antibiotics prescribed for these diagnoses has increased significantly.
This trend resulted in a 15% decline in the total proportion of outpatient visits in which antibiotics were prescribed. However,
because outpatient visits increased 17% over this time period, the population burden of outpatient antibiotic prescriptions
changed little.
Keywords antibiotics - prescribing - United States - NAMCS - NHAMCS
Dr. Edwards has received grants from Aventis, VaxGen, and GlaxoSmithKline. Dr. Griffin has consulted for Merck and received
a grant from Pfizer.
This material is based upon work supported by the Veterans Affairs Clinical Research Center of Excellence (CRCoE)(C. L. R.,
M. R. G.).
Public Health Service award K12 RR017697 for the Vanderbilt Mentored Clinical Research Scholar Program (N. B. H.).
Vanderbilt Center for Education and Research Vanderbilt Center for Education and Research on Therapeutics, Vanderbilt University
School of Medicine (M. R. G.).
Geriatric Research Education and Clinical Center, Veterans Affairs, Tennessee Valley Healthcare System, Nashville, Tenn (C.
L. R., M. R. G., R. S. D.)
General Clinical Research Center, Vanderbilt University School of Medicine, Nashville, Tenn (K. M. E.).