BackgroundThis study aimed to test the effectiveness and implementation of a complex integrated care intervention for older adults. We collected both quantitative and qualitative data, which is recommended in evaluating complex interventions to gain a comprehensive understanding of key success factors. Often, congruence is sought and considered desirable when integrating the findings from both data types. However, data are not always congruent, nor is it suboptimal when incongruence occurs, as we illustrate in this case study. We present the divergent findings from a large community-based implementation-effectiveness hybrid type II trial, and how the struggle to reconcile incongruent results yielded rich insights informing the next steps for translational research on the intervention being tested.MethodsPrevious foundational research, including a pilot study and randomized controlled trial (RCT), showed promising results and supported proceeding with a multi-site pragmatic hybrid type II effectiveness-implementation RCT. This recent RCT was undertaken and quantitative and qualitative data were collected to inform the effectiveness and implementation evaluation. To synthesize the findings and guide integration of this large body of evidence, we developed a conceptual model which combined two existing frameworks: the Consolidated Framework for Implementation Research and Quintuple Aim. We used this model to identify the evidence and relate it to relevant implementation and intervention determinants/outcomes. We then synthesized the evidence to distall the main messages regarding the future of the intervention, which involved reconciling apparently discrepant findings from the quantitative and qualitative approaches.ResultsThe current RCT showed no statistically significant effect for participants for the primary (or secondary) outcomes yet the implementation evaluation consistently found perceived benefits of the intervention for patients, providers, and the healthcare system. Qualitative evidence was critical in understanding contextual factors potentially responsible for the absence of a treatment effect (e.g., COVID-19), strategies to overcome challenges experienced in participant engagement and intervention delivery, and recent policy/practice setting changes which showed strong alignment with the intervention and supported its future implementation.ConclusionsWith the goal of the hybrid type II effectiveness and implementation study in mind, stakeholders encouraged proceeding with a scalability assessment to consider the evidence from the current trial within the context of our prior research, the broader literature for similar interventions, and the ever-changing policy context.Trial registrationclinicaltrials.gov NCT03664583. Registration date: September 10, 2018.