Table 1. Characteristics of the six randomized controlled trials included in the final analysis.

Study (year)	No. of patient		Age (yr)	Treatments protocol		Methods of evaluating efficacies
	Azithromyci n group (n=452)	Doxycycline group (n=454)		Azithromycin group	Doxycycline group
Parsad et al. (2001)10	30 (6.6)	30 (6.6)	≥16	Azithromycin 500 mg 4 d/mo+topical 0.05% tretinoin	100 mg doxycycline once daily+topical 0.05% tretinoin cream	1. Investigator's assessment of treatment using a 4 point scale
Kus et al. (2005)13	25 (5.5)	26 (5.7)	18~30	Azithromycin 500 mg 3 d/wk (1st mo), 2 d/wk (2nd mo), once a week (3rd mo)	Doxycycline 100 mg twice a day (1st mo), once daily (2nd mo, 3rd mo)	1. Facial inflammatory, non-inflammatory acne lesion counts
						2. Patient's own assessment of treatment using a 5 point scale
						3. Investigator's assessment of treatment (treatment responses were expressed as percentages)
Babaeinejad et al. (2011)12	50 (11.1)	50 (11.0)	≥13	Azithromycin 500 mg 4 d/mo	100 mg doxycycline once daily	1. Investigator's assessment of treatment (treatment responses were expressed as percentages)
Maleszka et al. (2011)15	120 (26.5)	120 (26.4)	≥14	Azithromycin 500 mg 3 d/wk (1st wk), followed by 500 mg weekly	100 mg doxycycline twice a day (1st d), followed by 100 mg doxycycline once daily	1. Facial inflammatory acne lesion counts
						2. Investigator's assessment of treatment (treatment responses were expressed as percentages)
Moravvej et al. (2012)14	34 (7.5)	35 (7.7)	18~30	Azithromycin 500 mg 3 d/wk	100 mg doxycycline daily	1. Facial inflammatory, non-inflammatory acne lesion counts
						2. Patient's own assessment of treatment using a 5 point scale
						3. Investigator's assessment of treatment (treatment responses were expressed as percentages)
Ullah et al. (2014)16	193 (42.7)	193 (42.5)	14~30	Azithromycin 500 mg 4 d/mo	100 mg doxycycline daily	1. Investigator's assessment of treatment (treatment responses were expressed as percentages)