Resting energy expenditure in cystic fibrosis patients decreases after lung transplantation, which improves validity of prediction equations for energy requirement

F.M. Hollander-Kraaijeveld, A.S. van Lanen, N.M. de Roos, H.G.M. Heijerman, E.A. van de Graaf

Thursday 5 march 2020

14:00 - 14:10h at Leo Franssen zaal

Parallel session: Parallel sessie XIV– Klinische abstracts

Background: Resting energy expenditure (REE) is used to tailor dietary counselling in cystic fibrosis (CF) patients before and after lung transplantation (LTx). Cross-sectional studies suggest REE decreases after LTx. Follow-up data in patients are lacking. Therefore, we assessed REE in CF patients before and after LTx, and compared measured REE to predicted REE using Harris-Benedict (1919, 1984), Schofield and FAO/WHO/UNU prediction equations.

Methods: REE was measured in 14 CF patients (mean age 32, range 15 - 49 years) in fasted state using indirect calorimetry; once before and 4 times after LTx, with a 2-year follow-up. REE was expressed as kcal/day and kcal/kg fat-free mass (FFM)/day. Linear mixed models were used to analyze time differences.

Results: Before LTx, mean measured REE was 1787 kcal/day or 40 kcal/kg FFM, which was 122 – 124% of predicted REE, depending on the prediction equation. Twelve months after LTx, this had significantly decreased to 1620 kcal/day (P<.001) or 33 kcal/kg FFM (P<.001), which was 107 – 108% predicted (all P≤.001). A year after LTx, values stabilized and prediction was accurate (i.e. within 10% of measured REE) in about two thirds of patients. Body mass index (BMI), fat-free mass index (FFMI) and pulmonary function improved significantly after LTx (all below P=.012).

Conclusions: This longitudinal study indicates that measured REE in CF patients decreases by almost 10% after LTx. Prediction equations consistently underestimate energy needs, even after LTx. If measuring REE is no option, it seems prudent to expect energy demands to be at least 20% higher than predicted.