Nine randomised controlled trials were included: there were 4 placebo-controlled studies on phenobarbital, 3 on diazepam, one on pyridoxine, and one on phenytoin. In one of the phenobarbital studies, valproate was also compared with placebo.There were 707 and 716 children in the active treatment and placebo groups, respectively.
The risk of recurrences was significantly lower in children receiving continuous phenobarbital therapy than placebo (OR 0.54, 95% CI: 0.33, 0.90, p=0.017).
The OR for recurrences in the valproate versus placebo group was 0.09 (95% CI 0.01, 0.78, p=0.011).
No difference in risk was found for recurrences between children receiving intermittent diazepam and placebo (OR 0.81, 95% CI: 0.54, 1.22, p=0.31).
The risk for pyridoxine or phenytoin did not differ from the risk among children receiving placebo.
Four children would have to be treated with valproate (95% CI: 2, 11) or eight children would have to be treated with phenobarbital (95% CI: 5, 27) continuously, to prevent one febrile seizure.
The test for heterogeneity performed before including the studies in the meta-analysis showed insignificant results, justifying the combination of the data.