Six studies, comprising 832 patients under the age of two years were included.
The methodological quality of the six studies ranged from 27% to 73% of the maximum score. The studies published after 1981 scored better (range 60 to 73%) than those published earlier (range 27-43%).
Four individual studies reported, at short term, a statistically significant reduction in clinical failure, persistent effusion at two weeks, persistent bacterial growth (at 2-7 days), or otoscopic signs of AOM in favour of antibiotic treatment. Three studies mentioned long term results, and no differences were found between antibiotic therapy and placebo.
The authors were able to extract data for the quantitative analysis from four studies. Clinical improvement in the four studies included in the quantitative analysis was assessed after a period lasting from 24 hours to six days after the start of treatment. The common odds ratio of clinical improvement in patients treated with antibiotics, compared with the reference group was 1.31 (95% CI: 0.83, 2.08).
Restricting the quantitative analysis to studies with a methodological quality of 60% or more did not change the results (OR= 1.42; 95% CI: 0.85, 2.39). Exclusion of one study, in which only non-severe episodes were included, yielded an odds ratio of 1.10 (95% CI: 0.56, 2.15). Exclusion of one study with rather strong positive results, yielded an odds ratio of 1.20 (95% CI: 0.74, 1.94).