Accepted for/Published in: Journal of Medical Internet Research
Date Submitted: Jul 18, 2025
Date Accepted: Mar 17, 2026
Warning: This is an author submission that is not peer-reviewed or edited. Preprints - unless they show as "accepted" - should not be relied on to guide clinical practice or health-related behavior and should not be reported in news media as established information.
A Stepped Care Approach for Digital Engagement: Analyzing Demand, Costs, and Simulation-Based Insights
ABSTRACT
Background:
Digital health interventions often require strategies to engage non-adherent participants. A stepped care approach, starting with low-resource intensity strategies and escalating to high-resource intensity strategies as needed, can optimize resource utilization. Yet its application in digital dietary interventions and associated cost implications remain underexplored.
Objective:
This study aimed to 1) evaluate the demand and implementation costs of a stepped care engagement approach within iSIPsmarter, a digital behavioral intervention to reduce sugar-sweetened beverage (SSB) consumption in rural Appalachia, and 2) simulate the impact of varying monitoring costs, demand, and stepped care intensity on overall resource use and implementation costs to guide optimization and future implementation.
Methods:
iSIPsmarter’s stepped care process combined automated and human-supported components to enhance engagement across six interactive web-based modules (“Cores”). During the nine-week intervention, participants who did not complete a Core received an initial automated email. Study coordinators monitored progress, and if the Core remained incomplete, initiated stepped care: a text (Step 1, low-resource intensity) after seven days, followed by up to three telephone attempts (Step 2, high-resource intensity) after another seven days. Following Step 2, non-completers were marked non-adherent but could resume adherence by completing the Core within the intervention period. To estimate implementation costs, time spent on human-supported steps was tracked: monitoring averaged 3 minutes ($1.68), texts 2.83 minutes ($1.58), and calls 5.1 minutes ($2.85). Simulations explored 18 scenarios (not directly observable in the trial) varying in monitoring efficiencies (20%, 50%, and 80% of trial-observed monitoring time/costs), stepped care demand (20%, 50%, and 80% of participants needing stepped care), and intervention intensity (low versus high-resource intensity), using longitudinally nested data draws.
Results:
Among 126 participants, the average number of stepped care contacts was 1.2 (SD= 1.3): 52 (41%) required none, 42 (33%) needed it for one Core, 26 (21%) for two, and 7 (6%) for three. On average, participants completed 5.2 (SD=1.6) of 6 Cores. The mean stepped care implementation time per participant was 26.46 (SD=11.02) minutes, costing $14.80 (SD=6.16). Monitoring accounted for 78% ($11.61; SD=3.91) of this, with initial monitoring alone contributing 58% ($8.51; SD=2.35). Simulations showed wide variation in time required and corresponding cost based on monitoring efficiency. In low-demand, low-intensity scenarios, efficient monitoring required 7.47 minutes ($4.18), while inefficient monitoring required 19.58 minutes ($10.95). In high-demand, high-intensity scenarios, efficient monitoring led to 101.8 minutes ($56.92), while inefficient monitoring increased time to 146.32 minutes and cost to $81.82.
Conclusions:
iSIPsmarter demonstrated high engagement, with most participants needing at least one stepped care contact to complete the Cores. Monitoring was the main cost driver, and simulations showed that improving monitoring efficiency can significantly reduce costs, particularly in low-demand settings. These findings highlight the potential for resource-efficient engagement strategies in digital dietary interventions. Clinical Trial: NCT05030753
Citation
