ProMuscle in Practice: Effectiveness of a combined resistance exercise and nutrition intervention to promote maintenance of physical functioning of community-dwelling elderly in a real-life setting

Rationale and objective:

The age related loss of skeletal muscle mass and muscle function can lead to a decrease in physical functioning, decreased independence, and subsequently increased health care costs. Previous clinical intervention studies have shown that the loss of muscle mass and strength in (frail) elderly can be counteracted using a combination of progressive resistance type exercise training and increased dietary protein intake. In a recent pilot study including both pre-frail and non-frail participants, such a combined intervention has been adapted to real life settings and successfully implemented. Before this adapted intervention program can be widely implemented in real life settings , its (cost)-effectiveness should first be verified and the implementation process should be further optimized to fit within current health care practice. Therefore, the present study aims to study the effectiveness of the adapted intervention and a behaviour maintenance period in (pre)frail community-dwelling elderly, as well as perform an economic and process evaluation in a real-life setting.

Study design: Randomised, controlled, multicentre, phased intervention trial with a parallel design.



Study population: 200 community-dwelling, (pre-)frail elderly (≥ 65 years) living in one of the five intervention municipalities.



Intervention: During the 12 week intervention period, the intervention group receives tailored progressive resistance exercise training twice a week (one hour per training). The trainings will involve small groups and will be guided by physiotherapists. In addition, dieticians will provide individual dietary advice to increase protein intake to 25 grams of protein per main meal, using protein rich products. During the 12 weeks maintenance period, the intervention group is informed about local exercise- and nutrition facilities supporting maintenance of the new lifestyle. The control group receives no exercise- or nutrition guidance, and no referral to local exercise- or nutrition options during the first 24 weeks.



Main study parameters: The primary outcomes are differences in change in physical functioning between the intervention and control group, at 12 weeks (T1) and 24 weeks (T2). The secondary outcomes related to the effectiveness of the intervention include differences between the intervention and control group in change in muscle strength, muscle mass, quality of life, and social participation, at 12 weeks (T1) and 24 weeks (T2). Care use and Quality of Life is also assessed at week 6 and 18. For the economic evaluation, cost-effectiveness and cost-utility parameters, i.e. costs per effect (SPPB change) and QALY (defined by EQ5D), will be measured. Measures on effect outcomes and costs will also be performed at T3 in the control group. For the process evaluation process indicators including acceptability, applicability, implementation integrity, dose received, and factors for success and failure will be monitored.

Progressive resistance exercise and increased dietary protein intake enhances physical functioning, quality of life, muscle strength and lean body mass in frail elderly, in a real-life setting, and reduces healthcare costs/utilization.

Parameters are assessed in both intervention groups at baseline, 12 weeks and 24 weeks. Parameters are also assessed at 36 weeks in the control group. Process evaluation parameters are also collected during the intervention.

The intervention subjects will receive a 12 week intensive intervention and a 12 week maintenance period. The intensive intervention consists of:

1) Twice weekly1-hour progressive resistance-type exercise training, in groups, supervised by physiotherapists

2) Increased dietary protein intake during the main meals, using protein-rich products, supervised by a dietitian

During the maintenance period the participants will be introduced to local exercise and nutrition facilities. Multiple activities will be organized to stimulate participants to maintain the active lifestyle and an adequate protein consumption.

The control group receives no treatment in the first 24 weeks, and will receive the maintenance period after 24 weeks.