Table 2.

Randomized Trials of Antibiotics in Acute Bronchitis^legend

First Author, Year (reference)	No. of Subjects	Antibiotic	Main Outcome Measure	Study Result (95% CI)∗	Standardized Effect Size (95% CI)†
Howie, 1970 (31)	836	Demethyl-chlortetracycline	Average days of purulent spit	0.3‡	Not available‡
Stott, 1976 (33)	207	Doxycycline	Days of yellow spit	0.6 (−0.2 to 1.4)	0.20 (−0.08 to 0.48)
Franks, 1984 (30)	54	Trimethoprim/sulfamethoxazole	Cough amount score	0.2 (−0.2 to 0.6)§	0.25 (−0.30 to 0.79)
Williamson, 1984 (34)	69	Doxycycline	Days of purulent sputum	−0.2 (−1.2 to 0.8)	−0.09 (−0.57 to 0.38)
Brickfield, 1986 (28)	50	Erythromycin	Sputum production score	0.2‡, ¶	Not available‡
Dunlay, 1987 (29)	45	Erythromycin	Sputum production score on day 10	0.5 (0.1 to 0.9)#	0.80 (0.20 to 1.41)
Scherl, 1987 (32)	31	Doxycycline	Days of sputum	1.9 (−0.2 to 4.0)	0.64 (−0.08 to 1.36)
Verheij, 1994 (35)	140	Doxycycline	Days of productive cough	0.5 (−0.4 to 1.4)	0.18 (−0.15 to 0.52)
Hueston, 1994 (36)	23	Erythromycin	Days of productive cough	−0.4 (−2.4 to 1.6)	−0.21 (−1.14 to 0.72)
King, 1996 (37)	91	Erythromycin	Days of sputum production	0.7 (−1.3 to 2.7)	0.14 (−0.27 to 0.55)

^∗Result is the mean in the antibiotic group minus the mean in the placebo group for the main outcome measure. A positive result indicates a benefit from antibiotics. A negative result indicates a benefit from placebo.

^†Effect size is the difference between the mean outcome in the antibiotic and placebo groups divided by the pooled standard deviation.

^‡These studies did not provide data that allowed calculation of a confidence interval or a continuous outcome measure, and therefore could not be included in the overall summary effect size.

^§Cough amount score was a patient-reported score on a severity scale of 1 to 3.

^¶Sputum production score was a patient-reported score on a severity scale of 1 to 4.

^#Sputum production score was a patient-reported score on a severity scale of 1 to 5.

^legendCI = confidence interval.