Context: Antibiotic use is associated with increased rates of antibiotic-resistant organisms. A previous study has shown that colds, upper respiratory tract infections, and bronchitis account for nearly one third of all antibiotic prescribing by ambulatory care physicians. How frequently antibiotics are prescribed for these conditions and for and by whom is not known.

Objectives: To measure antibiotic prescription rates and to identify predictors of antibiotic use for adults diagnosed as having colds, upper respiratory tract infections, and bronchitis in the United States.

Design: Sample survey of practicing physicians participating in the National Ambulatory Medical Care Survey, 1992.

Setting: Office-based physician practices.

Subjects: Physicians (n=1529) completing patient record forms for adult office visits (n=28787).

Main outcome measures: Antibiotic prescriptions for colds, upper respiratory tract infections, and bronchitis.

Results: Office visits for colds, upper respiratory tract infections, and bronchitis resulted in approximately 12 million antibiotic prescriptions, accounting for 21% of all antibiotic prescriptions to adults in 1992. A total of 51 % of patients diagnosed as having colds, 52% of patients diagnosed as having upper respiratory tract infections, and 66% of patients diagnosed as having bronchitis were treated with antibiotics. Female sex (odds ratio [OR], 1.65; 95% confidence interval [CI], 1.05-2.62) and rural practice location (OR, 2.25; 95% CI, 1.33-3.80) were associated with greater antibiotic prescription rates, whereas black race (OR, 0.44; 95% CI, 0.21-0.93) was associated with lower antibiotic prescription rates. Patient age, Hispanic ethnicity, geographic region, physician specialty, and payment sources were not associated with antibiotic prescription rates in the bivariate analysis. Multivariate logistic regression analysis identified only rural practice location (adjusted OR, 2.58; 95% CI, 1.39-4.76) to be independently associated with more frequent antibiotic prescriptions for colds, upper respiratory tract infections, and bronchitis.

Conclusion: Although antibiotics have little or no benefit for colds, upper respiratory tract infections, or bronchitis, these conditions account for a sizable proportion of total antibiotic prescriptions for adults by office-based physicians in the United States. Overuse of antibiotics is widespread across geographical areas, medical specialties, and payment sources. Therefore, effective strategies for changing prescribing behavior for these conditions will need to be broad based.