Energy expenditure in kidney transplant patients
Résumé
After kidney transplantation weight gain is associated with adverse
effects such as hypertension, dyslipidemia, insulin resistance, increased
vascular risk and deterioration of graft function. The identification weight
gain mechanisms would be helpful to propose preventive strategies. This
study addressed energy expenditure (EE) changes after kidney
transplantation. Fifteen male patients aged 52.8
7
1.7 years, transplanted
for one to 6 years, non-diabetic and with stable renal function (calculated
creatinine clearance, 30–90 ml/min/1.73 m
2
) were included. They received
anticalcineurin drugs but not corticosteroids. Nine healthy volunteers
matched for age (54.2
7
1.9 years) and fat-free mass (FFM) were considered
as controls. Body composition, including FFM, was determined by DEXA. EE
was measured under controlled conditions (24 hours in calorimetric
chambers) during the following activities: sleep, rest, meals, and 2 sessions
of 30 min of treadmill walking (4 and 5 km/h). The EE results are expressed
per kg of FFM, mean
7
SEM. FFM was respectively 62.0
7
2.3 and
62.3
7
2.7 kg in patients and controls (NS). EE during sleep was 15% higher
in patients than in controls (4.37
7
0.10 vs. 3.80
7
0.24 kJ/hour/kg FFM,
p
o
0.05). The 24h-EE also tended to be higher in patients compared to
controls (
þ
8%,
p
¼
0.057,158.31
7
3.90 vs. 146.13
7
4.35 kJ/day/kg FFM). No
significant difference was observed between patients and controls for the
EE during walking at 4 or 5 km/h, during meals and at rest.
In conclusion, in kidney transplant patient weight gain occurs despite
hyper-metabolism during sleep and over 24 h. Mechanisms of weight gain
therefore possibly involve changes in food intake and/or spontaneous
physical activity.