Randomised controlled trials (RCTs) that compared the efficacy and safety of the same antimicrobial agent for short versus long duration in patients with acute exacerbation of chronic bronchitis were eligible for inclusion. The antimicrobial was required to be given at the same dose and administered by the same route in each treatment arm. Both chronic bronchitis and acute exacerbations of chronic bronchitis were defined in the review.
The primary outcomes assessed were treatment success (defined as total cure or partial improvement of symptoms such that no further antimicrobial treatment was required) and drug-related adverse events in both the intention-to-treat and clinically evaluable populations. Secondary outcomes were all-cause mortality, long-term disease-related outcomes, withdrawals, incidence of diarrhoea, treatment success in microbiologically evaluable patients and pathogen eradication.
All included trials assessed oral antibiotics. The antimicrobials assessed were cefixime 400mg/daily, grepafloxacin 400 mg/daily, moxifloxacin 400mg/daily, levofloxacin 500 mg/daily, gatifloxacin 400mg/daily and clarithromycin 1000mg/daily. None of the trials allowed additional antibiotics
Two reviewers independently assessed the studies for inclusion in the review.