|Home | About | Journals | Submit | Contact Us | Français|
We thank Dr Narchi for raising a couple of important statistical issues.
The first point suggesting that emergency drug use may not be independent of duration of seizure is certainly valid statistically. Median duration time was significantly higher in those patients who were administered emergency anticonvulsant therapy compared to those who did not receive this treatment. However, when this variable was excluded from the regression model, the parameter estimates for the remaining variables were virtually identical to the results presented in table 2; only the p values differed slightly for duration (p=0.01, previously p=0.10) and idiopathic aetiology (p=0.04, previously p=0.08).
From a clinical point of view, we felt that the importance of adjusting for emergency drug use in examining seizure recovery time outweighed the potential statistical problem outlined above and that the paper would be criticised if this variable was omitted. The robustness of the results to the addition and exclusion of the “drug use” variable would seem to indicate that this approach was justified.
The second point arises from some confusion over the inclusion of “seizure aetiology” as a categorical variable in the regression model. We can confirm that this was exactly the approach we took in the analysis and acknowledge that this may not have been clear in the Methods. We compared the relative effects on recovery time for acute symptomatic, idiopathic and remote symptomatic seizures compared to febrile seizures, the latter category being used as the baseline group.
Competing interests: None declared.