JMIR Publications

ABSTRACT

Background:

Achieving clinically significant weight loss through lifestyle interventions for obesity management is challenging for most individuals. Improving intervention effectiveness involves early identification of intervention non-responders and providing them with timely, tailored interventions. Early and frequent self-monitoring (SM) adherence predicts later weight loss success, making it a potential indicator for identifying non-responders in the initial phase.

Objective:

This study aimed to identify clinically meaningful participant subgroups based on longitudinal adherence to SM of diet, activity, and weight, over 6 months, as well as psychological predictors of participant subgroups from a Self-Determination Theory (SDT) perspective.

Methods:

This was a secondary data analysis of a 6-month digital lifestyle interventions for overweight/obese adults. Participants were instructed to perform daily SM on 3 targets: diet, activity, and weight. Data from 50 participants (mean age: 53.0 ± 12.6 years) were analyzed. Group-based multi-trajectory modeling were performed to identify subgroups with distinct trajectories in SM adherence across the 3 SM targets. Differences between subgroups were examined on changes in clinical outcomes (i.e., body weight, hemoglobin A1c (HbA1c)) and SDT constructs (i.e., eating-related autonomous motivation, perceived competence for diet) over 6 months, using linear mixed models.

Results:

Two distinct SM trajectory subgroups emerged: the “Lower SM Group” (42%), characterized by “all-round low and rapidly declining SM” and the “Higher SM Group” (58%), characterized by “moderate and declining diet and weight SM with high activity SM”. Since week 2, participants in the Lower SM Group exhibited significantly lower levels of diet (p = .0026), activity (p = .002), and weight SM (p = .022) compared to the higher SM group. For clinical outcomes, the Higher SM group achieved a significant reduction in body weight (-6.06 ± 0.87 kg, p < .0001) and HbA1c (-0.38 ± 0.11%, p = .0188), while the Lower SM group exhibited no improvements. For SDT constructs, both groups maintained high levels of autonomous motivation over 6 months. However, the Lower SM group experienced a significant decline in perceived competence (p = .005) compared to the Higher SM group, which remained a high level of perceived competence throughout the intervention (p = .089)

Conclusions:

The presence of the Lower SM Group highlights the value of using longitudinal SM adherence trajectories as an intervention response indicator. Future adaptive trials should identify non-responders within the initial 2 weeks based on their SM adherence and integrate intervention strategies to enhance perceived competence for diet to benefit non-responders. Clinical Trial: ClinicalTrials.gov NCT05071287