Fidelity of the Face-it health promotion intervention for women with recent gestational diabetes

Abstract Introduction According to the 2021 British Medical Research Council 2021 framework, a feasibility study aims to assess intervention-specific progression criteria. Fidelity is a critical criterion because it concerns how an intervention is implemented as intended. Fidelity conceptualisation has expanded beyond intervention adherence to encompass participant engagement, i.e., how well they receive and enact the intervention, but these latter aspects achieve little attention. We aimed to assess the fidelity of the Face-it intervention, a health promotion intervention for women with a history of gestational diabetes mellitus and their families. The intervention consisted of three home visits and health technology delivered by health visitors/coaches. Our fidelity assessment included: i) training of the health visitors/coaches ii) the delivery, iii) receipt, and iv) enactment of the intervention. Methods The National Institutes for Behaviour Change Consortium’s (NIHBCC) framework for fidelity was used to assess four elements of fidelity. Data were collected from 150 women using intervention checklists, health technology logs and the virtual climate care questionnaire, which measured autonomy supportiveness from the intervention. Results The health visitors/coaches received four training days before the implementation and 16 hours throughout the intervention delivery. 73.3% of women completed three home visits, and 91.3% of women registered as health technology users. The participants perceived the intervention to be autonomy supportive, encourage health behaviour change and provide effective possibilities for health behaviour change, even though the delivery of the health technology varied greatly. Conclusions The Face-it intervention was largely implemented as intended. Using the NIHBCC framework, we expanded our fidelity conceptualisation and gained important insight into the feasibility of the intervention and interplay between delivery, receipt, and enactment.