Pulmonary nodules are common incidental findings on thoracic imaging examinations. This study sought to determine whether antibiotic use is associated with any improvement in nodule appearance and to identify clinical findings and nodule characteristics potentially influencing the decision to prescribe antibiotics.
Electronic medical records were reviewed of outpatients referred to a metropolitan cancer center for pulmonary nodules seen on chest CT scans who did not undergo biopsy. The primary end point was the appearance of each nodule on the first follow-up scan. A subset analysis was performed for patients manifesting symptoms or radiographic findings suggesting infection. An analysis was performed to determine what clinical and radiographic findings were associated with the decision to prescribe antibiotics.
Between January 2003 and December 2004, 143 evaluations were performed for 293 nodules. Antibiotics were prescribed to 34 (24%) evaluations. A trend toward improvement was seen with antibiotic use, which was not significant. The percentage of nodules that improved was 33% among those receiving antibiotics and 27% among those who did not (odds ratio 1.33; 95% CI, 0.55-3.27). Among 63 patients with pulmonary symptoms, 41% of nodules improved among those receiving antibiotics and 28% among those who did not (odds ratio 1.78; 95% CI, 0.42-7.78).The decision to prescribe antibiotics was associated only with larger nodule size and bronchiectasis.
These data do not support antibiotic use for pulmonary nodules. However, the trend toward improved nodule appearance suggests that larger prospective trials are warranted to clarify the role of antibiotics in managing lung nodules.