This Canadian study was not so bad. The 33% of patients who did not get a CT
scan had a good proxy measure of neurological function at 14 days which was
shown to be sensitive and specific when compared with those who had a scan.
363 patients were lost to follow-up, this represents 88% follow-up. I have
trouble believing that there are enough patients in this 'lost to follow up
group' who had adverse outcomes to significantly bias the findings. The rate
of necessary neurosurgical intervention in the study group was 1% 44
patients. If the rate was similar in the lost to follow-up group, then only
4 patients would have been missed. If it was twice then only 7 patients.
This would not have altered the overall findings much. (Actually 88%
follow-up in a cohort study on Emergency patients is very impressive.) The
1358 patients who were not included in the study would not affect the
validity of the results, but it is a matter of judgement whether this group
affects the generalisibility of the findings to our practice. I am
reasonably happy that the group of patients studied is comparable to my own
practice. (Valididity should always come ahead of generlisibility, you can't
generalise an invalid result!)
GCS is usually the best and most consistent way of assessing neurology
following head injury. Nausea and lethargy are very soft symptoms and very
difficult to quantify. I still stand by my initial classification.
Adrian Boyle
----- Original Message -----
From: <[log in to unmask]>
To: <[log in to unmask]>
Sent: Sunday, February 03, 2002 3:07 AM
Subject: Wafarinised head injuries
> I am actually not so convinced by the Canadian study you are referring to
(Stiell
> et al., Lancet 2001 375:1391-96). There are some significant flaws. For
example,
> 33% of the patients were not scanned but underwent a telephone follow-up
(how
> does this compares to a CT?), of these 363 patients were lost to follow up
(for
> what we know, they might have died) and were not even included in the
analysis!
> And as many as 1358 eligible patients were not included in the study.
> About your classification, do you only rely on the GCS? What about
vomiting,
> headache, unequal pupils, seizures, etc?
>
> M. Della Corte
> Staff Grade ED
> Oxford
>
>
>
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