This is a nice review on azithromycin to prevent chronic obstructive pulmonary disease exacerbations (COPD exacerbations).
A recent Cochrane analysis and a retrospective VA study were both found that continuous azithromycin use decreased the incidence of COPD exacerbations in patients with mild-moderate COPD (OR 0.55). However, azithromycin use did not improve quality of life and was associated with a slightly increased cardiovascular risk (by increasing the QT interval) and increased the risk of hearing loss. See the link below for details:
Do you think patients with COPD should be placed on continuous azithromycin?
JAMA. 2014;311(21):2225-2226. doi:10.1001/jama.2014.4929.
Am J Respir Crit Care Med. 2014 May 15;189(10):1173-80. doi: 10.1164/rccm.201402-0385CI.
JAMA. 2014 Jun 4;311(21):2199-208. doi: 10.1001/jama.2014.4304.