P336 Evolution of the body composition of people with cystic fibrosis 6 months after the introduction of treatment with exacaftor/tezacaftor/ivacaftor (ETI)

Elexacaftor/tezacaftor/ivacaftor (ETI) has significantly improved the prognosis and quality of life of people with cystic fibrosis (pwCF). Among all the benefit, an average weight gain of 4.2 kg is described one year after the initiation. The distribution of this weight gain between the different body compartments such as fat mass (FM) or lean mass(LM) is not described. LM is composed of active cell mass (ACM), corresponding mainly to muscles and organs and extracellular mass (ECM). The aim of this study is to assess the modification of the body composition by impedancemetry 6 months after the ETI in pwCF. Prospective monocentric study conducted at the Lille adult cystic center. The evaluation was carried out before the introduction of ETI and at 6 months after with an impedancemetry (Biacorpus RX4000, Karlsruhe, Allemagne), spirometry and collection of clinical data. Continuous variables are expressed as means ± SD. M0-M6 comparisons are performed by paired T-test for variables with normal distribution. 32 patients were included, 37.5% were women, median age at 31 [23.8; 38] years. The clinical characteristics and impedance data at baseline and at M6 are summarized (table 1). In 72% (n = 23) of our pwCF, the percentage of lean mass decreased significantly at M6 and eight subjects (25%) had a paradoxical reduction in their absolute mass of ACM. Tabled 1Baseline (n = 32)M6 (n = 32)pWeight (kg)61 ± 9.964.8 ± 10.2<0.01BMI21.6 ± 2.123 ± 2.32<0.01Fat Mass (kg)14.2 ± 7.815.9 ± 6.2<0.01Lean Mass (kg)47.1 ± 9.249.2 ± 8.9<0.01ACM (kg)23.7 ± 6.824.6 ± 6.10.06ECM (kg)23.4 ± 2.924.6 ± 3.6< 0.01VEMS (%)62.6 ± 18,777,3 ± 17.3<0.01CVF (%)84.3 ± 14.995.3 ± 15.2<0.01 Open table in a new tab After 6 months of treatment by ETI, respiratory function and nutritional status are improved with a significant gain in FM and LM but not in ACM. One quarter of patients exhibit an decrease in absolute ACM. These results suggest the need for physical activity associated with ETI treatment to improve the increase of ACM.