Although acute bronchitis usually has a viral etiology and antibiotics are not indicated for treatment of this condition, they are prescribed in 60 to 80 percent of cases of acute bronchitis. Previous studies assessed the overuse of antibiotics among adults in general; the prescribing patterns and reasons for antibiotic prescribing in patients 65 years and older with acute bronchitis have only recently been studied. Because previous antibiotic use is a risk factor for antibiotic resistance in subsequent bacterial infections, it may be particularly important to investigate inappropriate antibiotic use in older patients, who are at greater risk of morbidity and mortality when they get bacterial infections. To understand what variables play a role in prescribing antibiotics for acute bronchitis in this age group, Steinman and colleagues studied the elements of the clinical evaluation and how they relate to the decision to prescribe antibiotics.

The authors reviewed 722 charts of patients 65 years and older who were diagnosed with acute respiratory infections. Of a final sample of 671 patients, 198 had acute bronchitis. Patients with lung disease, chronic bronchitis, or concurrent acute respiratory infections were excluded.

Vital signs frequently were not documented in the patients' charts. When they were documented, temperatures higher than 37.7°C (100°F) were noted in 7 percent of patients, 15 percent had a temperature of 37.2°C to 37.7° C (99.0°F to 99.9°F), and 8 percent had a heart rate of 100 beats per minute or more. Duration of illness longer than seven days was noted in more than one half of the patients. In addition, one half of the patients had significant chronic comorbidities. In this study, 83 percent of the patients received antibiotics, most commonly a macrolide. Antibiotic prescription rates did not vary in patients with or without comorbidities. Men received antibiotics more frequently than women, but of all the factors reviewed, sex was the only variable associated with antibiotic prescription.

Although the data suggested that significant abnormalities in the study participants were uncommon, antibiotics were frequently prescribed, but with no discernible pattern. Vital signs had little influence on whether or not antibiotics were prescribed in this age group. It appears that antibiotics were prescribed simply on the basis of a diagnosis of acute bronchitis, unrelated to risk factors for serious complications. Chest radiographs were used in only 10 percent of patients to distinguish pneumonia from bronchitis.

The authors conclude that a large percentage of patients are being exposed to unnecessary antibiotics, even though those antibiotics have the potential for side effects and resistance, and often are expensive.