Date of Award

2020

Degree Type

Thesis

Degree Name

Doctor of Philosophy

School

School of Medical & Health Sciences

First Advisor

Professor Rob Newton

Second Advisor

Professor Gary Lee

Third Advisor

Associate Professor Philippa Lyons-Wall

Fourth Advisor

Dr Carolyn McIntyre

Abstract

Background: Patients with malignant pleural disease (MPD) have advanced cancer and high symptom burden. Goals of patient care are to optimise health-related quality-of-life (HR-QoL) and participation in daily physical activities. Supportive care interventions such as nutrition and exercise could offer benefit to patients. However, there is a lack of information on the prevalence of low muscle mass (i.e., pre-sarcopenia), malnutrition, inactivity and poor physical functioning in patients with MPD. Additionally, little is known about the factors associated with development of pre-sarcopenia and malnutrition or their associations with patient outcomes.

Purpose: The objectives were to: 1) characterise physical activity levels and their relationship with patient outcomes; 2) compare methodology used to classify presarcopenia; 3) determine the prevalence of pre-sarcopenia and malnutrition and investigate their relationship with activity behaviours and HR-QoL; 3) determine the prevalence of poor physical functioning and nutritional outcomes throughout the two years postdiagnosis; 5) describe body composition changes and investigate their relationship with physical activity and dietary intake; and 6) examine the effects of nutritional status and dietary intake on outcomes of an exercise intervention.

Methods: Three studies in patients with MPD were conducted: a cross-sectional study, a prospective observational study, and an exercise intervention study. Participants in the cross-sectional study (n=46) underwent assessment of physical activity levels (accelerometer). Participants in the observational (n=36) and exercise intervention (n=33) studies underwent assessment of nutritional status (Patient-Generated Subjective Global Assessment), body composition (computed tomography [CT], dual-energy x-ray absorptiometry [DXA]), physical activity levels (accelerometer), physical functioning (Timed Up-and-Go), HR-QoL (Short-Form 36; Functional Assessment of Cancer Therapy [FACT]-General), appetite (FACT-Anorexia Cachexia Scale) and fatigue (FACTFatigue). Participants in the intervention study underwent additional tests of physical functioning (Six-Minute Walk Test, chair rise) and muscular strength (1-repetition maximum leg press).

Results: In the cross-sectional study, 89% of participants did not meet physical activity guidelines. There was moderate agreement between CT and DXA for the classification of pre-sarcopenia (ĸ=0.424; p=0.006). Fifty-four percent of participants were pre-sarcopenic, and 38% were malnourished. Compared to participants with normal muscle mass, presarcopenic participants were more sedentary (p=0.001) and participated in less light activity (p=0.008). Compared to participants who were well-nourished, malnourished participants had poorer HR-QoL (p0.05). In the exercise intervention, participants with adequate dietary intake (40%) had a significant increase in muscle mass (p=0.004), while participants with inadequate dietary intake (60%) maintained muscle mass (p=0.737). There were no differences between well-nourished and malnourished participants with respect to completion, adherence or tolerance of the intervention (p>0.05).

Conclusion: Overall, there were high rates of pre-sarcopenia, malnutrition, inactivity, and poor physical functioning among participants with MPD. Pre-sarcopenia and malnutrition were associated with negative patient outcomes. Muscle loss was associated with decline in physical activity. The results indicate dietary intake could influence the effects of exercise. Interventions that target both physical activity and dietary intake could be most impactful.

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