Cost-effectiveness of a Diet and Resistance Exercise Intervention in Community-Dwelling Older Adults : ProMuscle in Practice

Objectives: Ageing is associated with a decline in functioning and a loss of independence, which will lead to increased health care costs in the future. The ProMuscle in Practice intervention was found to be effective in improving muscle strength, muscle mass, and functioning of older adults. The current study assesses the cost-effectiveness and perceived benefits of the intervention. Design: Trial-based cost-effectiveness analysis complemented by interviews. Setting and participants: A total of 168 community-dwelling older adults were included. Intervention participants started with a 12-week intensive support program, comprising resistance exercise guided by physiotherapists and consultations with a dietitian to increase protein intake. To maintain the adapted lifestyle pattern, they continued with a 12-week moderate support intervention. The control group received usual care. Methods: Costs and outcomes were measured at baseline, after 12 and 24 weeks. Costs were assessed from a societal perspective. Health care use, out-of-pocket costs, and productivity losses were measured using questionnaires. Intervention costs were quantified according to bottom-up micro-costing. Outcomes included quality of life (EQ-5D-5L) and physical functioning (Short Physical Performance Battery [SPPB]). Bootstrap analyses were used to generate cost-effectiveness planes and acceptability curves. Interviews with participants and professionals were conducted after 24 weeks to measure perceived benefits. Results: An Incremental Cost-Effectiveness Ratio of €2988 ($3385)/point increase in SPPB was found. The intervention has an 82.4% probability of being cost-effective at a willingness to pay (WTP) of €12.000 ($13.559)/point increase in SPPB. No change in quality of life was found according to EQ-5D-5L. Interviews, however, revealed a wide range of function-related perceived benefits. Conclusions and Implications: At a WTP of €12.000 ($13.559)/point increase in SPPB, the intervention was found to have an 82.4% probability of being cost-effective. Because generic quality of life questionnaires seem unable to detect subtle changes in public health interventions, future studies are advised to include targeted and specific questionnaires.