Accepted for/Published in: JMIR mHealth and uHealth
Date Submitted: Jan 22, 2025
Date Accepted: Jun 10, 2026
Self-monitoring over time: A secondary data analysis of a randomized controlled trial on Weight Loss
ABSTRACT
Background:
Behavior change support systems aim to shape, modify, or strengthen attitudes or behaviors without using coercion or deception. One of the main features of the persuasive system design is self-monitoring (SMO), which provides means for users to continuously track their own performance or status, facilitating goal attainment.
Objective:
To comprehend if the frequency of self-input weight (SMO frequency) alone or its interaction through time affects weight loss among users of a mobile health behavior change support system (mHBCSS).
Methods:
We examined a subset of 75 individuals from an RCT using a mHBCSS, who kept self-monitoring weight for at least 6 months of usage. The quantile regression method was performed in R software. The dependent variable was weight loss through time based on self-input data. The independent variables were the SMO frequency at each time periods and the interaction between SMO and the time periods. A sensitivity analysis of multiple imputation procedure was performed to assess the robustness of the quantile regression.
Results:
The time periods variable was significant in the 25th percentile [QR coefficient -1.164, CI95% -1.453, -0.756] and in the 50th percentile [QR coefficient -0.603; CI95% -0.733, -0.493]. The interaction variable was significant in the 50th [QR coefficient -0.018; CI95% -0.047, -0.003] and 75th [QR coefficient -0.036; CI95% -0.051, -0.027] percentiles. SMO frequency alone was not statistically significant.
Conclusions:
The results of this trial show that the effect of SMO on weight loss decreases over time. Thus, additional strategies must be implemented to maintain or enhance long-term effectiveness. Clinical Trial: Clinical Trials Identifier: NCT04558801
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