Adaptive vs Monthly Support for Weight-Loss Maintenance: A Randomized Clinical Trial.

Importance: Weight regain is common after the end of initial weight-loss treatment. Existing extended care programs (which typically provide sessions once per month) improve long-term weight-loss outcomes, but with only modest effect vs control. Objective: To determine whether weight regain is reduced via provision of telephone-based extended care on an adaptive (triggered by a study algorithm that estimates when individuals are at high risk for weight regain) vs static (provided once per month) schedule. Design, Setting, and Participants: A randomized clinical trial conducted between October 2019 and November 2024 in areas within driving distance of Gainesville, Florida. Adults with obesity enrolled in a 16-week weight-loss program; those who lost 5% or more of their baseline weight were eligible for randomization to 1 of 2 maintenance care conditions. Intervention: Participants received 20 months of telephone-based extended care support, delivered individually by a trained interventionist, either on an adaptive or static schedule. Main Outcomes and Measures: The primary outcome was weight change from month 4 (end of initial intervention) to month 24. Results: The 255 participants (mean [SD] age, 50.6 [11.3] years; 209 [82.0%] women; 51 [20.0%] Black, 25 [9.8%] Hispanic or Latino, and 170 [66.7%] non-Hispanic White) were randomized to an adaptive (128 participants) or static (127 participants) group. Weight regain from month 4 to 24 was 1.27 (95% CI, 0.07 to 2.47) kg in the adaptive vs 1.75 (95% CI, 0.43 to 3.06) kg in the static group, with no difference by condition. At month 24, adaptive participants maintained a mean (SD) weight loss of 8.1% (7.8%) from initial intervention baseline while static participants maintained 7.9% (8.5%); there was not a significant difference in the proportion of participants maintaining weight loss of 5% or more (adaptive, 59.5%; static, 59.8%). Conclusions and relevance: In this randomized clinical trial, participants in both conditions were successful at maintaining initial weight loss 20 months after the end of a weight-loss program, but providing extended care on an adaptive schedule did not confer additional benefit vs the once-per-month static schedule. Future research should investigate whether more precise algorithms of high-risk periods for weight regain can be developed and whether these models can improve weight maintenance outcomes. Moreover, given success of participants in both conditions at maintaining initial weight loss, future research should also investigate methods of improving the implementation and dissemination potential of telephone-based extended care interventions. Trial Registration: ClinicalTrials.gov Identifier: NCT04116853.