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Evidence summaries

Antibiotics for Acute Bronchitis

Antibiotics appear to have a modest beneficial effect in some patients diagnosed with acute bronchitis. Level of evidence: "B"

A Cochrane review [Abstract] 1 included 17 studies with a total of 5 099 subjects with acute bronchitis, both smokers and non-smokers.

Atfollow-up, there was no difference in participants described as being clinically improved between antibiotic and placebo groups (tableT1). Participants given antibiotics had a shorter mean cough duration, were less likely to have a cough, have a night cough, show no improvement on clinician's global assessment, or have abnormal lung findings. Antibiotic-treated patients also had a reduction in days feeling ill and a reduction in days with limited activity. No differences were observed in presence of a productive cough at follow up, proportions with activity limitations at follow up, and mean duration of productive cough. Adverse effects were increased in the antibiotic group. The most commonly reported side effects involved gastrointestinal symptoms such as nausea, vomiting or diarrhoea. Headaches, skin rash and vaginitis also occurred. Side effects seemed mild as only 0% to 13% (overall 3.7%) withdrew for this reason and no deaths were reported.

Authors' comment: The magnitude of the modest beneficial effect of antibiotics in patients with acute bronchitis needs to be considered in the broader context of potential side effects, medicalization for a self-limiting condition, increased resistance to respiratory pathogens and cost of antibiotic treatment. It is possible that older patients with multimorbidities may not have been recruited to trials so the evidence guiding decision making in this group of patients is less certain.

Antibiotis versus no antibiotics in acute bronchitis.

OutcomeParticipants (studies)Antibiotics*Placebo*RR (95% CI)NNT
Clinically improved3 841 (11)73%67%1.07 (0.99 to 1.15)22
Cough at follow-up visit275 (4)33%51%0.64 (0.49 to 0.85)6
Night cough at follow-up visit538 (4)30%45%0.67 (0.54 to 0.83)7
Productive cough at follow-up visit713 (7)37%37%0.97 (0.82 to 1.16)
Limitation in work or activities at follow-up visit478 (5)10%14%0.75 (0.46 to 1.22)
Not improved by physician's global assessment at follow-up visit891 (6)14%23%0.61 (0.48 to 0.79)25
Abnormal lung exam at follow-up visit613 (5)18%35%0.54 (0.41 to 0.70)6
Adverse effects3 496 (12)23%19%1.20 (1.05 to 1.36)5
OutcomeParticipants (studies)Mean difference (95% CI)
Mean number of days of cough2 776 (7)-0.46 (-0.87 to -0.04) days
Mean number of days of productive cough699 (6)-0.43 (-0.93 to 0.07) days
Mean number of days of impaired activities767 (6)-0.49 (-0.94 to -0.04) days
Mean number of days of feeling ill809 (5)-0.64 (-1.16 to -0.13) days
*crude prevalence
Comment: The quality of evidence is downgraded by inconsistency (variability in results).

Clinical comment:Testing acute phase reactants (CRP) might assist in identifying patients who do not benefit from antibiotics from those for whom antibiotics could be considered.

References

  • Smith SM, Fahey T, Smucny J et al. Antibiotics for acute bronchitis. Cochrane Database Syst Rev 2017;(6):CD000245. [PubMed]

Primary/Secondary Keywords