Antibiotics for acute bronchitis.

BACKGROUND: Antibiotic treatment of acute bronchitis, which is one of the most common illnesses seen in primary care, is controversial. Most clinicians prescribe antibiotics in spite of expert recommendations against this practice. OBJECTIVES: People with acute bronchitis may show little evidence of bacterial infection. If effective, antibiotics could shorten the course of the disease. However if they are not effective, the risk of antibiotic resistance may be increased. The objective of this review was to assess the effects of antibiotic treatment for patients with a clinical diagnosis of acute bronchitis. SEARCH STRATEGY: We searched Medline, Embase, reference lists of articles and the authors' personal collections up to 1996, and Scisearch from 1989 to 1996. SELECTION CRITERIA: Randomised trials comparing any antibiotic therapy with placebo in acute bronchitis. DATA COLLECTION AND ANALYSIS: At least two reviewers extracted data and assessed trial quality. MAIN RESULTS: Eight trials involving 750 patients aged eight to over 65 and including smokers and non-smokers were included. The quality of the trials was variable. A variety of outcome measures were assessed. In many cases, only outcomes that showed a statistically significant difference between groups were reported. Overall, patients receiving antibiotics had slightly better outcomes than did those receiving placebo. They were less likely to report feeling unwell at a follow up visit (odds ratio 0.42, 95% confidence interval 0.22 to 0.82), to show no improvement on physician assessment (odds ratio 0.43; 0.23 to 0.79), or to have abnormal lung findings (odds ratio 0.33, 95% confidence interval 0.13 to 0.86), and had a more rapid return to work or usual activities (weighted mean difference 0.7 days earlier, 95% confidence interval 0.2 to 1. 3). Antibiotic-treated patients reported significantly more adverse effects (odds ratio 1.64; 1.05 to 2.57) such as nausea, vomiting, headache, skin rash or vaginitis. REVIEWER'S CONCLUSIONS: Antibiotics appear to have a modest beneficial effect in the treatment of acute bronchitis, with a corresponding small risk of adverse effects. The benefits of antibiotics may be overestimated in this analysis because of the tendency of published reports to include complete data on only the outcomes found to be statistically significant.