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Table I. Descriptives of study variables
Study variable n = 118
Days since amputation at admission to acute rehabilitation, mean (SD) [range]
Days in acute rehabilitation, mean (SD) [range]
Creatinine at admission, mean (SD) [range]
Haemoglobin at admission, mean (SD) [range]
White blood cell count at admission, mean (SD) [range]
On haemodialysis at admission, n (%)
On wound vac at admission, n (%)
Taking intravenous antibiotics at admission, n (%)
Previous amputations, n (%)
Motor FIM admission and discharge, mean (SD) [range]
Motor FIM gain (admission – discharge motor FIM score, mean (SD) [range]
FIM efficiency (admission – discharge motor FIM score, mean (SD) [range] 15.3 (34.8) [2 to 288]
14 (7.1) [2 to 41]
1.61 (1.7) [0 to 8]
8.89 (1.42) [7 to 14]
9.12 (3.0) [4 to 19]
8 (11.3)
7 (9.9)
16 (22.5)
7 (9.9)
39.8 (10.8) [12–61] and 50.8 (14.1) [21 to 76]
10.87 (10.3) [–25 to 35]
0.84 (2.8) [–25 to 5]
SD: standard deviation; FIM: Functional Independence Measure.
12.6 g/dl); 22% were being treated with IV antibiotics
at the time of admission to the inpatient rehabilitation
unit. Ten percent of the sample had incisions requiring
wound vac, and 11% were on haemodialysis at the
time of admission to the inpatient rehabilitation unit.
Unplanned transfers from inpatient rehabilitation
Of the 118 patients, 19 (16.1%) required an unplanned
transfer from inpatient rehabilitation, with the most
common causes for transfer being infection, hypoxia
and renal failure (see Table II). The full model con-
taining all predictors was not statistically significant, χ 2
(13, n = 111) = 19.01, p = 0.12, indicating that the model
was not able to distinguish between those who did
Table II. Primary reasons for unplanned discharge from
rehabilitation unit
Reason Number of patients
Infection, unrelated to amputation
Acute kidney injury
Hypoxia/respiratory failure
Myocardial infarction
Amputation wound dehiscence
Amputation wound infection
Other wound complication
Altered mental status
Gastrointestinal bleeding
Total 5
4
3
2
1
1
1
1
1
19
Predictors of functional gains
Controlling variables of days since amputation, age,
admission motor FIM, and days in inpatient rehabili-
tation (for discharge motor FIM only) were entered
in Step 1, explaining 0.9% of the variance in FIM
efficiency, F (3, 93 = 0.29), p = 0.83. After entry of
infection factors (WBC, presence of IV antibiotics)
in Step 2, the total variance explained was only 6.7%,
F (5, 91) = 1.31, p = 0.26). After entry of poor wound
healing factors (creatinine, on haemodialysis, and on
wound vac) in Step 3, the total variance explained gai-
ned only a nominal amount, with 7.0%, F (8, 88) = 0.82,
p = 0.56. After entry of organ failure factors (diabetes,
haemoglobin value) in Step 4, there was no gain in
variance explanation with 7.0%, F (10, 86) = 0.65,
p = 0.77. In the final model adding previous amputa-
tion, shown in Table III, only 7.2% of the variance was
Table III. Logistic regression predicting likelihood of unplanned transfer from inpatient rehabilitation
95% confidence interval
B SE Wald df Sig. Exp(B) Lower Intravenous antibiotics a
Creatinine –0.18 0.13 1.91 1 0.17 0.84 0.65 1.08
–1.18
0.27 1.12
0.31 1.10
0.77 1
1 0.29
0.38 0.31
1.32 0.03
0.71 2.77
2.42
Wound vac at admission c 0.49 1.53 0.10 1 0.75 1.63 0.08 32.88
–0.20 1.10 0.03 1 0.86 0.82 0.10 7.09
–0.48
0.18 0.74
0.29 0.43
0.42 1
1 0.51
0.52 0.62
1.20 0.15
0.69 2.63
2.10
–0.36
0.10 1.01
0.06 0.12
3.30 1
1 0.73
0.07 0.70
1.11 0.10
0.99 5.12
1.24
2.24
0.00
–0.07
–0.05
–2.05 0.81
0.03
0.05
0.04
4.11 7.71
0.00
1.57
1.26
0.25 1
1
1
1
1 0.01
0.96
0.21
0.26
0.62 9.40
1.00
0.94
0.95
0.13 1.93
0.95
0.84
0.88 45.74
1.05
1.04
1.04
White blood cells
On haemodialysis at admission b
Diabetes d
Haemoglobin
Previous amputation e
Length of stay
f
and did not have an unplanned transfer from inpatient
rehabilitation. The model explained between 15.7%
(Cox and Snell R square) and 29.6% (Nagelkerke
R-squared) of the variance in unplanned transfers
and correctly classified 88.3% of cases. As shown in
Table III, only gender made a unique and statistically
significant contribution to the model.
Gender
Age
Days since amputation
Admission motor FIM
Constant
a–e
referent=yes; f referent=male. SE: standard error; df: degree of freedom.
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