Page 47 - Physical activity in recipients of solid organ transplantation - Edwin J. van Adrichem

Physical activity in recipients of solid organ transplantation
Predictive Variables for 6MWD

e linear mixed-model analysis for 6MWD resulted in signi
length of hospital stay. A random intercept signi

cant e

ects for the variables
measurement moment, diagnosis category, sex, quadriceps and grip strength, FEV1

cantly increased the model

t. Grip
, and
strength did not have a signi
signi

cant coe

cient (P=. 139), but the model

t decreased

cantly (Akaike information criterion) when grip strength was omitted; therefore, grip
strength was retained in the model.

e results showed that women were expected to walk 30 m less and that a change
of 0.3 m was expected with every newton change in quadriceps and grip strength.
Furthermore, a change of 1.4 m was expected with every percentage change in FEV1
rejection did not improve the model

t, and no interaction e
ect was found. To facilitate
, and
with every additional day in the hospital, the expected 6MWD was reduced by 1.6 m (Tab.
2).

e intercept indicated that, on average, a man with pulmonary vascular disease, a
hospital stay of 39 days, a quadriceps strength of 250 N, a grip strength of 91 N, and an
FEV, 65% of the predicted value was expected to walk 432 meter at T0. Age, body mass
index, type of transplantation (double versus single), DLCO, total lung capacity, and

comparison, we added the model without grip strength to Table 2.

e pooled results from the mixed-model analysis after a series of 5 imputations of
missing data were comparable to the results obtained without data imputation. Signi e ects remained for measurement moment, diagnosis category, quadriceps strength,
F
cant EV1
and length of hospital stay. Sex and grip strength were not shown to be signi

cant in the
,
model after data imputation.
Reaching the Cuto

Point for 6MWD
Of the 84 recipients for whom data were available at T1 (discharge) and T3 (12 months),
35 (41.7%) reached the cuto
49 (58.3%) did not. Exploratory analyses showed signi

point of 82% of the predicted 6MWD or higher at T3, and

cant between group di

6MWD (percentage of predicted) at T1 and for diagnosis category, sex, length of hospital stay, FEV1, DLCO, and quadriceps and grip strength at T1 and T3 (Tab. 3). ese
signi

cant variables were entered into the logistic regression analysis. It was not possible to
erences for
retrieve reliable data on the contribution of DLCO from the regression analysis because of
an insu
A
cient number of data points. signi cant e ect found for
ect found for FEV1 at T1 could be interchangeably combined with quadriceps force at T1 or grip strength at T1 (Tab. 4). Both models showed an increase in
odds (to reach 82% of the predicted 6MWD at T3) of 4% with every percentage increase
in predicted FEV1
. In the model with quadriceps strength, the odds additionally increased
by 2% for every newton increase in quadriceps strength; for grip strength, a 6% increase in
odds was observed with every newton increase. Because quadriceps force and grip strength
were substantially correlated at T1 (r=.631, P<.001), they were not entered into the model
simultaneously so as to prevent multicollinearity.
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