Trajectories of muscle quantity, quality and function measurements in hospitalized older adults.

Aim: Acute sarcopenia is defined by the development of incident sarcopenia (low muscle quantity/quality and function) within 6 months of a stressor event. However, outcome measures for clinical trials have not been validated. This study aimed to characterize changes in muscle quantity, quality, strength, and physical function during and after hospitalization.

Methods: Patients aged ≥70 years admitted for elective colorectal surgery, emergency abdominal surgery or acute infections were recruited from a single university hospital. Assessments were carried out at baseline, and within 7 ± 2 days and 13 ± 1 weeks postoperatively or post-admission.

Results: A total of 79 participants (mean age 79 years, 39% female) were included. Physical function defined by the Patient-Reported Outcome Measures Information System T-score declined from baseline (42.3, 95% CI 40.2-44.3) to 7 days (36.6, 95% CI 34.5-38.8; P = 0.001), with improvement after 13 weeks (40.5, 95% CI 37.9-43.0). Changes in muscle quantity, quality and function measurements were overall heterogeneous, with few significant changes at the study population level. Change in rectus femoris echogenicity over 13 weeks correlated with changes in handgrip strength (r = 0.53; P < 0.001) and gait speed (r = 0.59; P = 0.003) over the same period.

Conclusions: Patient-Reported Outcome Measures Information System T-score provides a sensitive measure of change in physical function in hospitalized older patients. However, changes in muscle quantity, quality and function measurements were heterogeneous, and not significant at the study population level. Further research should assess for factors that might be predictive of changes within individuals to enable stratified interventions. Geriatr Gerontol Int 2022; 22: 311-318.