Abstract MP15: Promoting Lifestyle Change Via Real-time Feedback: Short-term Weight Loss Outcomes In The Smarter Trial
Authors: Burke Lora E , Sereika Susan M , Bizhanova Zhadyra , Parrmanto Bambang , Kariuki Jacob , Beatrice Britney , Loar India , Cheng Jessica , Pulantara I Wayan , Wang Yuhan , Cedillo Maribel , Conroy Molly 
Published: May 2021

Background:
Obesity is a major risk factor for CVD. Standard behavioral treatment (SBT) typically requires face-to-face sessions, is expensive, has limited evidence for sustained weight loss, and critically, is not available to many with obesity. Using innovative mobile technology to provide real-time tailored feedback (FB) to the self-monitoring (SM) of diet, physical activity, and weight can improve lifestyle and weight management habits. It can be accessible to those without access to SBT, or to those not wishing to participate in a structured, in-person program. We report short-term, 6-month weight findings from the SMARTER Trial.

Methods:
SMARTER tests the efficacy of adding automated FB to smartphone SM compared to SM alone on weight loss. We randomized 502 adults with overweight/obesity to either 1) SM alone (n=251) or 2) SM+FB (n=251). The SM+FB group received up to 3 FB pop-up messages/day on their smartphone which were tailored to data in SM entries and delivered at random times during waking hours. Participants used a smartphone app to self-report diet, a Fitbit Charge 2 to monitor physical activity, and a digital Bluetooth scale for weight tracking. At baseline, all had a 90-min one-on-one session with a dietitian on behavioral changes to target weight loss. Percent weight loss from baseline to 6 months and the percentage of participants having at least a 5% weight loss at 6 months were compared between treatment groups using an intention to treat (ITT) approach with either parametric or non-parametric group comparisons. Missing assessment weights at 6 months were imputed using participants’ weight tracking data.

Results:
Groups had similar demographic characteristics and anthropometric measures at baseline (all p≥.05). The sample was mostly female (79.5%,399/502) and white (84.3%, 423/502) with mean BMI of 33.10 ± 3.93 kg/m
2
. There was no difference between groups in having weight data available at 6 months (SM: 84.9%, 213/251), SM+FB: 83.7%, 210/251); p=.713). Based on ITT analyses, there was no significant difference between the two groups in mean percent weight loss from baseline to 6 months (SM: Mean= -3.24% [SD=5.27], SM+FB: Mean= -3.16% [SD=5.50]; p=.860). Similar results were obtained using non-parametric methods, further supporting no difference in percent weight loss between the groups (SM: Median= -2.25% [IQR=5.53], SM+FB: Median= -2.45% [IQR=6.88]; p=.962). Overall, 30.1%,151/502) achieved at least 5% weight loss at 6 months, with similar percentages between treatment groups (SM: 28.3%,71/251, SM+FB: 31.9%, 80/251); p=.381).

Conclusions:
These findings demonstrate excellent 6-month assessment completion rates. We did not support our hypothesis that participants in the SM+FB group would show greater weight loss at 6 months than those in the SM group. It is possible that weight loss outcomes may differ between groups in the second half of the 12-month intervention.