Randomised, clinically controlled trial of intensive geriatric rehabilitation in patients with hip fracture: subgroup analysis of patients with dementia

Dear Editor,

I read with interest the article by Dr Huusko1 and colleagues on the effect
of intensive geriatric rehabilitation on demented patients with hip
fracture. The study was probably the first randomized study with
predetermined subgroup analysis according to level of dementia on this
increasing patient group. The level of dementia was classified by mini
mental state examination score.2 The median length of hospital stay of hip
fracture patients with moderate dementia was 47 days in the intervention
group and 147 days in the control group (p = 0.04). The corresponding
figures for patients with mild dementia were 29 days in the intervention
group and 46.5 days in the control group (p = 0.002). It was concluded
that, hip fracture patients with mild or moderate dementia can often
return to the community if they are provided with active geriatric
rehabilitation. Pioneers work is never easy, either in this case. Even
though the study seemed to bee well conducted, the patients in the
intervention group were stated to have a highly significantly deeper level
of dementia as compared with the control group (p <0.001).

This was
considered as coincidental even though, such a difference in outcome would
be considered as a definitive proof of treatment effect in any medical
trial. The level of dementia was used as grouping variable when testing
the effect of intervention on the outcome, and thus probably had a
fundamental effect on the obtained results. Problem is that the level of
dementia was stated about one week after admission to the geriatric ward
of the central hospital or the local hospital, 10 days after surgery and
randomisation! Obviously the person making the mini mental scoring knew
the treatment group, and probably the person was different in the control,
and in the intervention group. This may have caused biased classification
of dementia, and may explain the observed difference in mini mental state
examination, between the study groups.3 Thereafter, recovery of patients
in the intervention group without true dementia may have been compared
with patients in the control group with mild dementia and so on, which
might explain significant part of the observed results in the study.

Obviously conduction of this kind of randomized study is very demanding,
but it would be highly recommended to try to blind assessment of the main
grouping factor.

Reference List

1. Huusko TM, Karppi P, Avikainen V, Kautiainen H, Sulkava R.
Randomised, clinically controlled trial of intensive geriatric
rehabilitation in patients with hip fracture: subgroup analysis of
patients with dementia. BMJ 2000;321:1107-1111.

2. Folstein MF, Folstein SE, McHugh PR. "Mini-mental state". A
practical method for grading the cognitive state of patients for the
clinician. Journal of Psychiatric Research 1975;12:189-198.

3. Schulz KF. Subverting randomization in controlled trials. JAMA
1995;274:1456-1458.