Table 3 Mean (SD) antibiotic use in the azithromycin and placebo groups during the study.

	Azithromycin	Placebo	Count ratio azithromycin/placebo estimate (95% CI)
Oral antibiotics
Number of courses
Total population	2.1 (0.4)	3.8 (0.5)	0.55 (0.36 to 0.85), p<0.01
Patients not infected with PA	2.1 (0.4)	3.6 (0.5)	0.59 (0.36 to 0.98), p<0.05
Patients infected with PA	2.2 (0.9)	4.5 (1.2)	0.49 (0.20 to 1.24), NS
Cumulative days of treatment
Total population	62 (13)	74 (13)	0.85 (0.50 to 1.44), NS
Patients not infected with PA	67 (15)	67 (15)	1.00 (0.54 to 1.88), NS
Patients infected with PA	53 (23)	96 (29)	0.56 (0.20 to 1.53), NS
IV antibiotics
Number of courses
Total population	0.8 (0.2)	1.6 (0.4)	0.48 (0.22 to 1.02), NS
Patients not infected with PA	0.4 (0.2)	0.5 (0.2)	0.80 (0.30 to 2.13), NS
Patients infected with PA	2.1 (0.8)	5.2 (1.2)	0.41 (0.17 to 0.96), p<0.05
Cumulative days of treatment
Total population	12 (4)	24 (5)	0.51 (0.24 to 1.09), NS
Patients not infected with PA	6 (2)	6 (2)	0.95 (0.36 to 2.52), NS
Patients infected with PA	34 (13)	81 (19)	0.42 (0.18 to 1.00), p = 0.05

SD, standard deviation; CI, confidence interval; PA, Pseudomonas aeruginosa; IV, intravenous; NS, not significant.

Sample sizes in the azithromycin and placebo groups were, respectively, 40 and 42 for the total population, 31 and 32 for the patients not infected with PA, and 9 and 10 for patients infected with PA.