Azithromycin for acute lower respiratory tract infections

Laopaiboon M, Panpanich R, Lerttrakarnnon P

Published Online:

November 9, 2011

Acute lower respiratory tract infections (LRTI) are one of the most common diagnoses in outpatient settings. They range from acute bronchitis and acute exacerbations of chronic bronchitis to pneumonia. Azithromycin is a subclass of macrolide antibiotics and is used to treat certain bacterial infections.

This review compared azithromycin with amoxycillin or amoxyclav in the treatment of acute LRTI in 16 trials. We were able to analyse the results from 15 trials with 2496 participants. The effects of azithromycin on cure, improvement or failure were not better than those of amoxycillin or amoxyclav. However, azithromycin seems to have a lower incidence of adverse events than amoxycillin or amoxyclav but it is not significant. Only three included trials showed adequate allocation concealment and most of the included trials were of unclear methodological quality with small sample sizes. We recommend future trials to be of good methodological quality and conducted on larger populations.

Abstract (click to read)

Background:

Acute lower respiratory tract infections (LRTI) range from acute bronchitis and acute exacerbations of chronic bronchitis to pneumonia. Approximately five million people die from acute respiratory tract infections annually. Among these, pneumonia represents the most frequent cause of mortality, hospitalisation and medical consultation. Azithromycin is a macrolide antibiotic, structurally modified from erythromycin and noted for its activity against some gram-negative organisms associated with respiratory tract infections, particularly Haemophilus influenzae (H. influenzae).

Objectives:

To compare the effectiveness of azithromycin to amoxycillin or amoxycillin/clavulanic acid (amoxyclav) in the treatment of LRTI, in terms of clinical failure, incidence of adverse events and microbial eradication.

Search strategy:

We searched the Cochrane Central Register of Controlled Trials (CENTRAL 2011, Issue 3), MEDLINE (January 1966 to July week 4, 2011) and EMBASE (January 1974 to August 2011).

Selection criteria:

Randomised controlled trials (RCTs) and quasi-RCTs, comparing azithromycin to amoxycillin or amoxycillin/clavulanic acid in participants with clinical evidence of an acute LRTI, such as acute bronchitis, pneumonia and acute exacerbation of chronic bronchitis.

Data collection and analysis:

The review authors independently assessed all potential studies identified from the searches for methodological quality. We extracted and analysed relevant data separately. We resolved discrepancies through discussion. We initially pooled all types of acute LRTI in the meta-analyses. We investigated the heterogeneity of results using the forest plot and Chi2 test. We also used the index of the I2 statistic to measure inconsistent results among trials. We conducted subgroup and sensitivity analyses.

Main results:

Sixteen trials involving 2648 participants were included. We were able to analyse 15 of the trials with 2496 participants. The pooled analysis of all the trials showed that there was no significant difference in the incidence of clinical failure on about days 10 to 14 between the two groups (risk ratio (RR), random-effects 1.09; 95% confidence interval (CI) 0.64 to 1.85). A subgroup analysis in trials with acute bronchitis participants showed significantly lower clinical failure in the azithromycin group compared to amoxycillin or amoxyclav (RR random-effects 0.63; 95% CI 0.45 to 0.88). A sensitivity analysis showed a non-significant reduction in clinical failure in azithromycin-treated participants (RR 0.55; 95% CI 0.25 to 1.21) in three adequately concealed studies, compared to RR 1.32; 95% CI 0.70 to 2.49 in 12 studies with inadequate concealment. Twelve trials reported the incidence of microbial eradication and there was no significant difference between the two groups (RR 0.95; 95% CI 0.87 to 1.03). The reduction of adverse events in the azithromycin group was RR 0.76 (95% CI 0.57 to 1.00).

Authors' conclusions:

There is unclear evidence that azithromycin is superior to amoxycillin or amoxyclav in treating acute LRTI. In patients with acute bronchitis of a suspected bacterial cause, azithromycin tends to be more effective in terms of lower incidence of treatment failure and adverse events than amoxycillin or amoxyclav. However, most studies were of unclear methodological quality and small sample sizes; future trials of high methodological quality and adequate sizes are needed.

This record should be cited as:

Laopaiboon M, Panpanich R, Lerttrakarnnon P. Azithromycin for acute lower respiratory tract infections. Cochrane Database of Systematic Reviews 2008, Issue 1. Art. No.: CD001954. DOI: 10.1002/14651858.CD001954.pub3

Assessed as up to date:

August 8, 2011

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Primary Review Group:

Acute Respiratory Infections Group

Health topics:

Infectious disease > Respiratory infections > Pneumonia

Infectious disease > Respiratory infections > Respiratory infections in general

Lungs & airways > Respiratory infections > Pneumonia

Lungs & airways > Respiratory infections > Respiratory infections in general

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Azithromycin for acute lower respiratory tract infections

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