Antibiotics for acute otitis media
- Review
- Results
- Comment
The
Achilles' heel of pooled analysis is that we concentrate on averages. No
individual is average, and we could do with much less concentration on whether
interventions work on average, but which patient characteristics determine
where the intervention works best. No does it work, but in whom does it work?
How can this be done? The answer is individual patient meta-analysis.
Theoretically this can provide really useful information. Such an analysis for
acute otitis media in children [1] holds out little indication that antibiotics
are useful in any children.
Review
Investigators
of trials were approached for individual patient data if their trials
randomised children aged 0-12 years with acute otitis media, compared
antibiotics with no treatment or placebo, and had pain and fever as an outcome.
Of 10 such trials, six provided data.
Outcomes
calculated were presence of pain (yes/no), fever (greater or less than
38˚C), or both at 3-7 days. A series of pre-defined subgroup analyses were
planned, together with logistic analysis to identify important correlates of
treatment efficacy.
Results
The
six trials essentially tested amoxicillin versus delayed treatment or placebo.
These six trials randomised 1,633 children. Overall, antibiotics reduced the
incidence of an extended course of acute otitis media at 3-7 days by 13%, with
an NNT of 8 (95% confidence interval 6-11).
Table
1 shows the overall result in more detail, together with those subgroups where
there was a lower (better) NNT. The analyses indicated that the effect of
antibiotics was modified by age, bilateral disease, and otorrhoea.
Table 1: Results of sub group analyses for antibiotics vs placebo in AOM
|
|
Extended course of acute otitis media (%)
|
|
|
| Subgroup |
Number in analysis
|
Antibiotic
|
Placebo
|
Relative risk
(95% CI)
|
NNT
(95% CI)
|
| Overall result |
1663
|
|
|
0.83 (0.78 to 0.89)
|
8 (6 to 11)
|
| <2 years with bilateral AOM |
273
|
30
|
55
|
0.64 (0.62 to 0.80)
|
4 (3 to 7)
|
| <2 years with unilateral AOM |
261
|
35
|
40
|
0.92 (0.76 to 1.1)
|
not calculated
|
| Otorrhoea present (any age) |
116
|
24
|
60
|
0.52 (0.37 to 0.73)
|
3 (2 to 5)
|
| Otorrhoea absent (any age) |
439
|
28
|
42
|
0.80 (0.70 to 0.92)
|
8 (4 to 20)
|
|
Outcome was pain, fever, or both
at 3-7 days
|
Comment
The
authors of this analysis go to great pains to describe possible limitations,
despite their individual patient analysis, and the great care they have taken
in a detailed and sophisticated analysis. The take-home message, though, is
that antibiotics seem to be most beneficial in younger children with bilateral
acute otitis media, and where there is otorrhoea.
How
much weight should we place on this? Not much, because differences between
antiobiotics and placebo disappeared by five or six days, numbers were small,
and what differences there were came from differences with placebo (look at
Table 1 carefully). This analysis nails down that there is no subgroup of
children for whom antibiotics can be really useful in acute otitis media,
unless there are complications or other consideration. It proves the utility of
individual patient analysis.
Reference:
- MM Rovers et al. Antibiotics for acute otitis media: a meta-analysis with individual patient data. Lancet 2006 368:1429-1435.
