Mattila, E., Hansen, S., Bundgaard, L., Ramsay, L., Dunning, A., Silva, MN., Harjumaa, M., Ermes, M., Marques, MM., Matos, M., Larsen, S., Encantado, JE., Santos, I., Horgan, G.W., O'Driscoll, R., Turicchi, J., Duarte, C., Palmeira, AL., Stubbs, J., Heitmann, BL. and Lähteenmäki, L.
||Background: Digital behavior change interventions (DBCIs) offer a promising channel for providing health promotion services.
However, user experience largely determines whether they are used, which is a precondition for effectiveness.
Objective: The primary aim of this study is to evaluate user experiences with the NoHoW Toolkit (TK)-a DBCI that targets
weight loss maintenance-over a 12-month period by using a mixed methods approach and to identify the main strengths and
weaknesses of the TK and the external factors affecting its adoption. The secondary aim is to objectively describe the measured
use of the TK and its association with user experience.
Methods: An 18-month, 2×2 factorial randomized controlled trial was conducted. The trial included 3 intervention arms receiving
an 18-week active intervention and a control arm. The user experience of the TK was assessed quantitatively through electronic
questionnaires after 1, 3, 6, and 12 months of use. The questionnaires also included open-ended items that were thematically
analyzed. Focus group interviews were conducted after 6 months of use and thematically analyzed to gain deeper insight into the
user experience. Log files of the TK were used to evaluate the number of visits to the TK, the total duration of time spent in the
TK, and information on intervention completion.
Results: The usability level of the TK was rated as satisfactory. User acceptance was rated as modest; this declined during the
trial in all the arms, as did the objectively measured use of the TK. The most appreciated features were weekly emails, graphs,
https://www.jmir.org/2022/1/e29302 J Med Internet Res 2022 | vol. 24 | iss. 1 | e29302 | p. 1
(page number not for citation purposes)
JOURNAL OF MEDICAL INTERNET RESEARCH Mattila et al
goal setting, and interactive exercises. The following 4 themes were identified in the qualitative data: engagement with features,
decline in use, external factors affecting user experience, and suggestions for improvements.
Conclusions: The long-term user experience of the TK highlighted the need to optimize the technical functioning, appearance,
and content of the DBCI before and during the trial, similar to how a commercial app would be optimized. In a trial setting, the
users should be made aware of how to use the intervention and what its requirements are, especially when there is more intensive
Trial Registration: ISRCTN Registry ISRCTN88405328; https://www.isrctn.com/ISRCTN88405328
International Registered Report Identifier (IRRID): RR2-10.1136/bmjopen-2019-029425
(J Med Internet Res 2022;24(1):e29302) doi: 10.2196/29302