Longitudinal Muscle Mass Trajectories and Their Prognostic Implications in Hemodialysis Patients

Muscle wasting is a critical concern in hemodialysis patients and is closely linked to adverse outcomes. While cross-sectional associations between low muscle mass and poor prognosis are well documented, the longitudinal trajectories of muscle mass and their predictive value for clinical outcomes remain incompletely characterized.

In this prospective cohort study, 283 hemodialysis patients undergoing at least three body composition assessments at 6-month intervals were included. We applied latent class trajectory modeling to identify distinct longitudinal trajectories of muscle mass change. The primary outcome was all-cause mortality. Secondary outcomes included all-cause hospitalization and cardiovascular (CV) mortality; however, CV mortality was evaluated descriptively because of the limited number of events (no adjusted modeling).

Muscle mass trajectories were modeled over a mean duration of 24.5 ± 9.2 months, and three distinct patterns were identified: increasing (17.0%), mild decline (56.5%), and progressive decline (26.5%), with annual appendicular skeletal muscle mass/m² changes of +10.2%, -2.3%, and -12.5%., respectively. Patients in the progressive decline group were older, had lower geriatric nutritional risk index, higher inflammatory markers, and a higher prevalence of cardiovascular disease. Multivariate analysis revealed that each 1-point decrease in geriatric nutritional risk index (odds ratio [OR], 1.12; 95% confidence interval [CI], 1.07-1.18), pre-existing cardiovascular disease (OR, 2.99; 95% CI, 1.57-5.69), and elevated systolic blood pressure (OR, 1.02; 95% CI, 1.002-1.03) independently predicted progressive muscle decline. During a median follow-up of 24 months, this group exhibited significantly increased risks of all-cause mortality (hazard ratio, 7.63; 95% CI, 2.78-20.90) and hospitalization (hazard ratio, 4.04; 95% CI, 2.01-8.10). CV deaths occurred in 1/48 (2.1%), 15/160 (9.4%), and 20/75 (26.7%) in the respective trajectory groups.

Distinct muscle mass trajectories were shown to stratify the risk of all-cause mortality and hospitalization. Therefore, incorporating repeated body composition assessments into routine care may facilitate early identification and targeted management.