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 in patients with a clinical diagnosis of acute bronchitis.
Search strategy: The authors searched MEDLINE, Embase, reference lists of articles, personal collections up to 1996 and Sci-search from 1989 to 1996.
Selection criteria: Randomized trials comparing any antibiotic therapy with placebo in acute bronchitis.
Data collection and analysis: At least two reviewers extracted data and assessed trial quality.
Primary results: The results of eight trials involving 750 patients from eight years of age to 65 and older and including smokers and nonsmokers were included. The quality of the trials was variable. A variety of outcome measures was assessed. In many cases, only outcomes that showed a statistically significant difference between groups were reported. Overall, patients taking antibiotics had slightly better outcomes than those taking placebo. They were less likely to report feeling unwell at a follow-up visit (odds ratio, 0.42; 95 percent confidence interval [CI] 0.22 to 0.82), to show no improvement on physician assessment (odds ratio, 0.43; CI, 0.23 to 0.79) or to have abnormal lung findings (odds ratio, 0.33; CI, 0.13 to 0.86), and had a more rapid return to work or usual activities (weighted mean difference, 0.7 days earlier; CI, 0.2 to 1.3). Antibiotic-treated patients reported significantly more adverse effects (odds ratio, 1.64; CI, 1.05 to 2.57), such as nausea, vomiting, headache, skin rash or vaginitis.
Reviewers' conclusions: Antibiotics appear to have a modest beneficial effect in the treatment of acute bronchitis, with a correspondingly 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 only on outcomes found to be statistically significant.