32-OR: The Advancing Care for T1D Obesity Network (ACT1ON) Sequential Multiple Assignment Randomized Trial Pilot Re-randomization Results

Background: Sequential Multiple Assignment Randomized Trials (SMARTs) efficiently address practical treatment comparison questions and adapt dynamically based on response. They may be useful for development of approaches to co-manage weight and glycemia T1D, which is critical yet challenging. Methods: Our SMART pilot with three diet periods enrolled young adults with T1D (BMI 27-39.9 kg/m²) . Participants were re-randomized after ∼3 months on the hypocaloric Look AHEAD (Low Fat) or Low Carbohydrate (Low Carb) ; or Mediterranean (Med, not calorie restricted) diet if Results: The proportion re-randomized was 57.9% and did not vary by diet. Weight was lost overall but insufficient weight loss was the most common reason for re-randomization for Low Fat and Med. An HbA1c increase ≥0.5% was most common on Med. Low diet acceptability was the most common reason for re-randomization on Low Carb. Conclusions: We achieved safe weight loss among young adults with T1D but observed heterogeneity in reasons for re-randomization by diet, although differences were not statistically significant. A fully-powered efficacy trial may confirm our findings. Disclosure D.Igudesman: None. R.E.Pratley: Other Relationship; Bayer AG, Corcept Therapeutics, Dexcom, Inc., Hanmi Pharm. Co., Ltd., Merck & Co., Inc., Metavention, Novo Nordisk, Pfizer Inc., Poxel SA, Sanofi, Scohia Pharma Inc., Sun Pharmaceutical Industries Ltd. M.R.Kosorok: n/a. D.M.Maahs: Advisory Panel; Abbott Diabetes, Eli Lilly and Company, Medtronic, Novo Nordisk, Sanofi, Consultant; Aditx Therapeutics, Inc., Biospex. E.J.Mayer-davis: None. J.Crandell: n/a. T.Pokaprakarn: None. K.Corbin: None. D.P.Zaharieva: Research Support; Insulet Corporation, International Society for Pediatric and Adolescent Diabetes, Leona M. and Harry B. Helmsley Charitable Trust. A.Addala: None. J.Thomas: None. A.Casu: None. M.Riddell: Advisory Panel; Zealand Pharma A/S, Zucara Therapeutics, Consultant; Eli Lilly and Company, Jaeb Center for Health Research, Speaker's Bureau; Dexcom, Inc., Eli Lilly and Company, Novo Nordisk. Funding National Institutes of Health 1DP3DK113358