5 RCTs, including 4 double-blind trials with 1686 children, were included (total of 1765 children).
Number of trials and children assessing specified therapies was as follows:
Antibiotic plus decongestant plus antihistamine vs placebo (2 RCTs, 992 children).
Antibiotic plus decongestant vs placebo (1 RCT, 141 children).
Decongestant plus antihistamine vs placebo (1 RCT, 556 children).
Decongestant vs placebo (1 RCT, 79 children).
Mean validity scores for the 5 trials included in the meta- analysis ranged from 2.55 to 2.85 out of a maximum possible score of 3.
1705 children completed the trials out of the 1765 children entered. However, it was also reported that 208 children did not complete the study and that 121 were excluded due to illness, giving overall drop-out rate of 18.6%.
Overall 44% of those treated pharmacologically had total cure of OME at 4 weeks compared to 36% of the placebo group. Pooled effect size was weak (correlation coefficient R = 0.07, P = 0.0017). Mean NNT = 45.278 (range 3.27 to 200).
Other statistics of effect size included d, t r F, x, z and n. However no explanation of these terms was given, thus these results are not reported.