Physical activity and physical fitness in children after Orthotopic Liver Transplantation aged 6 -1 2 years

Children after Orthotopic Liver Transplantation (OLT) show a survival rate of
88% after 5 years, but this is accompanied by important co-morbidities such as
hypertension, atherosclerosis, reduced growth, obesity, lowered bone density,
osteoporosis, delayed motor development, increased cardio-vascular risk factors
and a lower exercise capacity.

Co-morbidities have to be reduced in order to improve the outcome in these
children. Most of the co-morbidities might be related to a lower level of
physical activity. One study published in 2001(1) showed a lower exercise
capacity in children (aged 10 and older) after OLT compared to matched
controls. However, since 2000, anti-rejection treatment after OLT has changed
importantly. The dose of corticosteroids has decreased and immune suppressors
with less side effects have been introduced. Following these changes there is
no documented evidence as to the affect on children*s activity levels post OLT.

Lower activity levels (and the associated complications/co-morbidity) in
children may play a crucial role in the survival rates for children post OLT.
Studies in infants with chronic diseases and hart-lung transplants have found
that these infants have a lower then normal activity level and as second
outcome parameter, a lower exercise capacity. A lower activity level is
correlated with complications like overweight and hypertension. This study will
investigate if infants with an OLT also have a lower activity pattern compared
to published data of healthy children.

Primary objective is to compare physical activity (time spent in moderate to
vigorous activity and physical activity level) and exercise capacity (VO2 peak)
in children after OLT with published data of healthy controls.

Secondary objective is to compare muscle strength, health related quality of
life / fatigue, pain, participation and body composition with published data of
healthy controls.

Cross-sectional study

Extent of the burden:
Measurements will be combined with a regular visit to the outpatient clinic of
the OLT Group. All efforts will be made to combine these measurements with
regular controls in our hospital. During the visits an aerobic exercise test
will be conducted. This is a well known test without risks for the child and
takes 45 minutes (the test itself 10 minutes). Testing of all the parameters
takes about one hour and 45 minutes in the hospital. At home children wear an
accelerometer for a week and fill in an activity diary. Filling in the diary
will cost approximately 15 minutes a day. Parents have to fill in two
questionnaires in the hospital which takes 10 minutes.

Risk:
Neither of these measures are related to increased risks.