Morphofunctional Assessment with Nutritional Ultrasound in Hemodialysis Patients Undergoing Six Months of Intradialytic Aerobic and Resistance Training: A Novel Multiparametric Approach

Abstract Background Sarcopenia, frailty and protein-energy wasting are highly prevalent and associated with adverse outcomes in maintenance hemodialysis. Intradialytic exercise may attenuate muscle loss, but combined aerobic-and-resistance programmes evaluated with a comprehensive morphofunctional assessment, including nutritional ultrasound (NUS), remain poorly characterised. We aimed to evaluate the feasibility of a multiparametric morphofunctional assessment, incorporating NUS, for monitoring the response to a six-month combined intradialytic exercise programme and the associated changes in muscle, nutritional status and body composition. Methods In a prospective, single-centre, observational pre–post study (Hospital General de Fuerteventura, Canary Islands, Spain), patients undertook a six-month combined aerobic and resistance intradialytic exercise programme (two sessions per week). Of 44 patients assessed, 21 commenced the programme and 17 completed six months (four withdrew after kidney transplantation). Assessments at baseline and six months included handgrip strength, anthropometry, bioelectrical impedance analysis (BIA), NUS, clinical scales (Fried phenotype, SARC-F, Malnutrition–Inflammation Score (MIS), KDQOL-36) and dialysis adequacy. Within-patient changes were analysed with paired t or Wilcoxon tests and the exact McNemar test, with Benjamini–Hochberg false-discovery-rate (FDR) correction within domains. Results Handgrip strength increased from 23.3 to 27.1 kg (FDR = 0.002; Cohen's dz = 1.11) and rectus femoris cross-sectional area from 2.62 to 3.24 cm² (FDR = 0.030). Phase angle (4.53 to 5.01°; FDR = 0.028) and lean tissue index (FDR = 0.021) rose, fat tissue mass fell (40.3 to 36.7 kg; FDR = 0.028), and dialysis adequacy improved (Kt/V 1.40 to 1.62; FDR = 0.005). Frailty, sarcopenia risk and malnutrition–inflammation scores all improved (FDR < 0.05), as did physical quality-of-life and burden-of-disease scores (p < 0.05). The programme was well tolerated, no serious exercise-related adverse events and no exercise-related withdrawals. Conclusions A multiparametric morphofunctional assessment incorporating NUS was feasible and captured consistent longitudinal changes during a six-month combined intradialytic exercise programme associated with improvements in muscle strength, body composition, nutritional–inflammatory status, dialysis adequacy and quality of life. NUS may represent a promising tool for longitudinal monitoring, although its comparative performance against established techniques remains to be established. These findings warrant confirmation in larger studies with a control group.