Evaluation of the Immediate Effects of Digital Intervention Modules for Goals, Planning and Coping Planning on Physical Activity: Secondary Analysis of a Randomized Controlled Trial (Preprint)

BACKGROUND The use of digital interventions can be accurately monitored via log files. However, monitoring engagement with intervention goals or enactment of the actual behaviors targeted by the intervention is more difficult and is usually evaluated based on pre-post measurements in a controlled trial. OBJECTIVE To evaluate if engaging with two digital intervention modules focusing on physical activity goals and action plans, and coping with barriers had immediate effects on the actual physical activity behavior. METHODS The NoHoW Toolkit (TK) was a digital intervention developed for supporting long-term weight loss maintenance, evaluated in a 2 x 2 factorial randomized controlled trial. The TK contained various modules based on behavioral self-regulation and motivation theories, and contextual emotion regulation approaches, and involved continuous tracking of weight and physical activity through connected commercial devices (Fitbit Aria TM and Charge 2 TM). Two of the four trial arms had access to two modules directly targeting physical activity, i.e. a module for goal setting and action planning (“Goal”) and a module for identifying barriers and coping planning (“Barriers”). Module visits and completion were determined based on TK log files and time spent in the module web page. Five physical activity metrics (steps; activity; energy expenditure; fairly active, very active and total active minutes; and distance) were compared before and after visiting and completing the modules to examine whether the modules had immediate or sustained effects on physical activity. Immediate effect was determined based on 7-day windows before and after the visit, and sustained effects were evaluated for weeks 1-8 after module completion. RESULTS Out of the 811 participants, 498 (61.4%) visited the Goal module and 406 (50.1%) visited the Barriers module. The Barriers module had an immediate effect on very active and total active minutes (before-median for very active minutes: 24.2min/day, interquartile range IQR 10.4–43.0min vs. after: 24.9min, IQR 10.0–46.3min; P=.047; before-median for total active minutes: 45.1min/day, interquartile range IQR 22.9–74.9min vs. after: 46.9min, IQR 22.4–78.4min; P=.029). The differences were larger when only completed Barriers modules were considered. Barriers module completion was also associated with sustained effects in fairly active and total active minutes for most of the eight weeks following module completion, and for three weeks in very active minutes. CONCLUSIONS The Barriers module had small significant immediate and sustained effects on active minutes measured by a wrist-worn activity tracker. Future interventions should pay attention to assessing barriers and planning coping mechanisms to overcome them. CLINICALTRIAL ISRTCN registry ISRCTN88405328; https://www.isrctn.com/ISRCTN88405328.