The impact of an Implementation Strategy Bundle on the adoption of a combined lifestyle intervention in multiple community care settings: A hybrid type III stepped wedge implementation effectiveness trial

Background : ProMuscle is an evidence-based combined lifestyle intervention to promote physical functioning in community-dwelling older adults. To address identified barriers for the implementation of ProMuscle in community care settings, a theory and practice-based Implementation Strategy Bundle (ISB) was developed. The current study aims to investigate the impact of this ISB on the adoption of ProMuscle in multiple community care settings. Methods : A 42-week hybrid type III stepped-wedge randomized cluster implementation- effectiveness trial was conducted in Dutch community care. Participating healthcare professionals (i.e. physical therapists and dieticians) were allocated to one of five clusters based on their geographical location. The ISB targets multiple barriers (knowledge, costs, internal and external network) with multicomponent implementation strategies tailored to participants’ contexts using an online tool. Participants were trained to deliver ProMuscle and started the implementation as usual (i.e. without implementation support). Every six weeks one cluster transitioned to the intervention group. During this transitional period, participants gained access to the ISB. The primary outcome, adoption of ProMuscle, was measured on eight consecutive time points with the Provider REport of Sustainment Scale (PRESS). Adoption was analyzed with linear mixed models with random cluster effects and fixed time effects, corrected for gender and occupation. Secondly, reach, fidelity, acceptability, and feasibility of ProMuscle were evaluated over time as well as physical functioning outcomes of participating older adults. Results : Thirty healthcare professionals participated, data of 27 could be included for analysis. The intervention group showed a statistically non-significant increase of adoption of 0.32 (95% CI: -0.18-0.81; p=0.21) compared with the control group. After 42 weeks, 51% of the healthcare professionals had delivered ProMuscle, and fidelity of ProMuscle was higher in the intervention group than in the control group. Acceptability of ProMuscle significantly declined over time. Conclusion: The findings highlight the complexity of implementing combined lifestyle interventions such as ProMuscle in multiple community care settings. No significant effect of the ISB on the adoption was found. The results of this study suggest contextual factors likely influenced the implementation. Further exploration is needed into whether contextual factors moderated the impact of the ISB on the adoption of ProMuscle. Trial registration: ClinicalTrials.gov (NCT05672004) registered at 12/07/2022.