A framework for monitoring intervention fidelity: The NOURISH trial

Nutrition can have a profound impact on chronic disease outcomes, but without periodic assessment of treatment fidelity, one cannot know whether the outcomes are due to an effective intervention or other unknown factors. Repeated measurement of fidelity of all treatments and across all interventionists will ensure the likelihood that treatment differences are maintained for the duration of the trial. This paper summarizes our efforts to assess treatment fidelity throughout the ongoing Phase III dietary intervention trial known as Nutrition effects on Brain Outcomes and Recovery in Stroke after Hospitalization (NOURISH), which tests whether acute stroke survivors' adoption of the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet will slow annual cognitive decline compared to those assigned to receive enhanced usual care.

Templates and measures for treatment fidelity were developed according to five key components of treatment fidelity for the NOURISH trial: (1) intervention design and protocol, (2) training of interventionists, (3) treatment delivery (includes content and process), (4) treatment receipt, and (5) treatment enactment.

Through periodic assessments of such measures, investigators ensured that the interventionists were delivering the intervention consistently according to protocol and learning what the participant understood and was willing to adopt. Moreover, the intervention was further refined to make it more responsive to the needs of the diverse participants during their stroke recovery.

The future success of disseminating and implementing public health programming for stroke recovery relies on finding the right balance between maintaining intervention fidelity and allowing for adaptability. NCT04337255.