Ecological Momentary Assessment of Behavioral and Psychosocial Predictors of Weight Loss Following Bariatric Surgery

Bariatric surgery is a powerful tool for producing significant and durable weight loss. Yet,
not all patients achieve initial weight loss success and many patients have weight regain as
early as 1-2 years post-surgery. Suboptimal weight loss patterns not fully explained by
surgical, demographic, and medical factors has led to greater emphasis on patient behaviors
evidenced by clinical guidelines that focus on appropriate eating and physical activity.
However, research to inform such guidelines typically has relied on imprecise measures or
not been specific to bariatric surgery. There is also little understanding of mechanisms by
which psychosocial factors influence outcomes. Thus, there is a need to: (a) measure
behaviors and psychosocial factors thought to be related to surgical outcomes (particularly
those emphasized in guidelines) using innovative strategies to maximize data quality, (b)
determine which behaviors and psychosocial factors are related to outcomes, and (c) explore
how psychosocial factors influence weight both directly and via influences on behavior. Our
research team was the first to employ innovative mobile health (mHealth) technology within
an Ecological Momentary Assessment (EMA) framework to measure adherence to recommended
behaviors at 6 months post-surgery. The investigators propose to build on this work by using
EMA to measure behavioral, psychosocial, and environmental factors over a longer period to
understand how they predict success and risk after surgery. An NIH-funded multi-sensor PiLR
HEALTH platform will integrate objective sensor data measuring behaviors and the
environments in which they are performed with self-report information collected via
smartphone in real-time and in patients' natural environment. Participants (N=100) recruited
from 2 ASMBS-designated centers of excellence will complete a 10-day EMA protocol
pre-surgery and at 3, 6, and 12 months post-surgery to assess recommended behaviors [e.g.,
meal frequency, PA], psychosocial indicators with the most prior evidence of an association
with surgical outcomes (e.g., mood/depression), and key environmental factors (e.g.,
type/quality of the food environment). Participants will also be weighed at the above time
points. Along with describing patterns in behaviors and their relation to weight loss, the
investigators will test causal models to understand how complex systems of behavioral,
psychosocial, and environmental factors affect weight loss, and to identify optimal targets
for intervention. This project has the potential to build a much more sophisticated and
valid understanding of who is and is not successful after bariatric surgery and why. This
new understanding will directly contribute to improved (i.e., specific, consistent, and
validated) guidelines for recommended pre and postoperative behaviors, which could lead to
improved surgical outcomes. The enhanced understanding will also inform behavioral,
psychosocial, and environmental targets for intervention that are mostly likely to improve
surgical outcomes.