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R. Cheng et al.
our results are consistent with previous studies (e.g.
female gender as a risk factor for unplanned transfer).
Furthermore, our sample did exclude certain dysvas-
cular amputee patients, which should be taken into ac-
count when interpreting the results. We did not include
patients who initially went home after amputation or
patients who were admitted months after amputation
for the purpose of prosthetic training, because we felt
they represented patients who were significantly more
medically stable and less prone to complications than
those admitted to inpatient rehabilitation immediately
following amputation. Also, a small proportion of
patients were transferred and re-admitted to inpatient
rehabilitation several times. In these cases, only the
patient’s first rehabilitation admission was analysed, as
the goal of this study was to identify factors that could
predict a patient’s likelihood of a major medical com-
plication necessitating acute transfer, before the patient
is identified as being at high risk of decompensation.
In addition, this study examined each risk factor for
unplanned transfer or FIM gains independently and
does not does not account for the aggregate effect of
multiple comorbidities. Thus, the results do not account
for the possibility that multiple comorbidities may
have an additive effect, greater than the sum of each
individual comorbidity. Another limitation is that the
data for our regression models analysing motor FIM
and FIM efficiency are limited to patients who com-
pleted rehabilitation, and did not include patients who
developed medical complications necessitating transfer
to an acute medical service. Furthermore, it is notable
that clinical change indices suggested that only 20%
of the sample exceeded motor FIM gains that were un-
likely due to measurement error, although effect sizes
were quite large. One explanation is that much of the
benefit of inpatient rehabilitation for post-amputation
patients is from complication avoidance and patient
education, and that FIM, as a gross measure of fun-
ction, may not fully capture the medical benefits of
inpatient rehabilitation for patients with amputations.
For example, many lower extremity amputees are
discharged at a wheelchair level, which significantly
lowers their motor FIM score potential. However, FIM
has been used as the primary outcome measure in other
research and is the current standard for evaluating in-
patient rehabilitation performance of lower extremity
amputees (14). For future studies, measures such as
self-reported perception of functional independence,
such as the SF-36 or Katz ADL disability tools, may be
considered as additional ways to measure any benefits
achieved in this patient population (16, 17).
Taken together, these results suggest that patients
undergoing lower extremity amputation due to vascular
disease benefit from inpatient rehabilitation despite the
www.medicaljournals.se/jrm
multiple comorbidities that are commonly associated
with this population. This study supports the notion that
dysvascular amputee patients should be considered for
inpatient rehabilitation despite having high levels of
medical complexity. This is especially true given the
increased risk of harm or decompensation that may
result from a lower level of care. Further research is
needed to determine how comorbidities in dysvascular
patients may affect the extent of functional gains in
inpatient rehabilitation, and larger sample sizes would
be needed to judge the reproducibility and generaliza-
bility of our findings across a wider range of patients.
ACKNOWLEDGEMENTS
Funding to partially support this study was received from the
University of Michigan Health System-Ann Arbor Center for
Independent Living Advanced Rehabilitation Research Training
Program, US Department of Education, National Institute of
Disability and Rehabilitation Research (H133P090008).
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