Acute Sarcopenia: the last remaining acute organ insufficiency

Welch, Carly (2023). Acute Sarcopenia: the last remaining acute organ insufficiency. University of Birmingham. Ph.D.

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Introduction: Acute sarcopenia is defined by incident sarcopenia (muscle insufficiency defined by low muscle strength with low muscle quantity or quality) within six months, normally following a stressor event. It is under-considered in clinical practice, but has potential to lead to reduced quality of life and adverse outcomes from hospitalisation itself.
Methods: I undertook two prospective studies, including (Study 1) hospitalised patients aged 70 years and older, and (Study 2) healthy volunteers aged 18-35. Study 1 involved serial assessments of muscle quantity, quality, and physical function in elective colorectal surgery, emergency abdominal surgery, and general medical (infective diagnosis) patients. Study 2 assessed the variability of muscle quantity and quality measurements performed with Bioelectrical Impedance Analysis (BIA) and ultrasound with position and exercise. In addition, a systematic review was performed to synthesise evidence for interventions to ameliorate negative changes in muscle quantity and function in hospitalised older adults.
Results: Eighty-one participants were recruited (mean age 79, 38.3% female) to Study 1. Serial assessments of muscle quantity, quality, and function were shown to be feasible and acceptable to participants. Variability in trajectories of muscle parameters was demonstrated, with some participants experiencing declines, and others experiencing improvements or recovery across timepoints. Baseline nutritional status and step count were shown to interact in determination of recovery of muscle quantity. Penalised regression models revealed that prescription of steroids was positively associated with sarcopenia at 7 days, and the presence of delirium was negatively associated with change in BATT to 7 days. Forty-four participants (mean age 26, 52% female) were recruited to Study 2. Ultrasound measurements were shown
to increase from the reclined to sitting position and after exercise, demonstrating the importance of ensuring protocol standardisation. Interventions identified within the systematic review included physical activity interventions (27 studies), nutritional interventions (11 studies), testosterone (1 study), GH (2 studies), nandrolone (1 study), erythropoietin (1 study), and Neuromuscular Electrical Stimulation (3 studies). Evidence for effectiveness/efficacy was limited.
Conclusions: Acute sarcopenia research in complex heterogeneous populations of older adults is acceptable and feasible to patients. Targeting interventions to patients most at risk (e.g. those on treatments with steroids) should be considered in future trials. Pragmatic multi-arm trials including physical activity, nutritional, and pharmaceutical agents (e.g. GH) are encouraged.

Type of Work: Thesis (Doctorates > Ph.D.)
Award Type: Doctorates > Ph.D.
Licence: All rights reserved
College/Faculty: Colleges (2008 onwards) > College of Medical & Dental Sciences
School or Department: Institute of Inflammation and Ageing
Funders: Medical Research Council


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