ACT1ON Phase 2 (SMART Pilot) and Phase 3 (Efficacy Trial Development)
Condition: Diabetes Mellitus, Type 1; Overweight and Obesity
MeSH terms: Diabetes Mellitus; Overweight; Diabetes Mellitus, Type 1
Study type: Interventional

Summary: 
      An initial pilot and feasibility study will be conducted using a Sequential, Multiple
      Assignment, Randomized Trial (SMART) design to identify acceptable and effective dietary
      strategies to optimize both glycemic control and weight management in young adults with Type
      1 diabetes (T1D). This pilot trial will include a ten-and-a-half month behavioral
      intervention, with co-primary outcomes of glycemic control (HbA1C and hypoglycemia) and
      weight loss. The pilot trial will assess acceptability and adherence to three distinct,
      evidence-based dietary approaches designed to address weight management and glycemic control.
      Behavioral counseling strategies, use of carbohydrate counting for insulin dosing, and
      encouragement of physical activity will be the same across the three dietary approaches.

      COVID-19 PROVISIONS: Due to restrictions in place on in-person visits due to COVID-19
      precautions, some subjects may remain in the study longer than 10.5 months. As of June 2020,
      the study transitioned to a completely virtual format. Those who were due for a measurement
      visit during the time that research activities were halted, prior to the approval of the
      virtual procedures, remained on the diet they were currently assigned to, supported by
      bi-weekly Registered Dietitian (RD) counseling, until they were able to be scheduled for a
      virtual visit.
    

Detailed description: 
      Eight-four participants will be randomized in total; 42 at the University of North Carolina
      (UNC), 42 at Stanford.

      COVID-19 Provisions: Due to impacts of COVID-19, the study was forced to cease recruitment
      early. 40 subjects were randomized at UNC and 29 were randomized at Stanford, for a total of
      69 subjects across sites.

      Procedures (methods):

      Three distinct dietary approaches will be tested. Dietary approaches are as follows:

      Diet 1: hypocaloric, moderate low fat (30% calories from fat) weight management based on the
      Look AHEAD study Diet 2: hypocaloric, low carbohydrate (15-20% calories from carbohydrate,
      59-63% as total fat (<10% saturated fat, at least 37% monounsaturated fat, remaining as
      polyunsaturated fat) Diet 3: advice to select a healthy Mediterranean dietary pattern with no
      caloric restriction

      Participants will complete measurement visits at baseline (-14 days), 3 mos, 6.5 mos, and 10
      mos. All visits transitioned to a virtual format as of 6/2020 due to COVID-19 provisions.

      Participants will complete a total of 23 intervention sessions over an approximately
      10-and-a-half month period (Eight longer sessions (teleconference) and 15 telephone
      check-ins)

      Participants will be randomized to one of the three diets for a minimum of a three-and-a-half
      month period. Re-randomization is possible following the 3 month and/or 6.5 month measurement
      visits. Re-randomization is based on acceptability of diet (self-report), non-severe
      hypoglycemic events (self-report), and not achieving significant weight change (defined as
      losing at least 2% of body weight from previous study visit), and worsening glycemic control
      (increase in Hemoglobin A1c of >/= 0.5% from previous study visit). Re-randomization will
      occur after the 14-day continuous glucose monitoring (CGM) wear period that will be initiated
      at each measurement visit.
    

Intervention name(s): Hypocaloric, low carbohydrate diet; Hypocaloric, moderate low fat diet; Mediterranean diet, no caloric restriction
Intervention type(s): Behavioral; Behavioral; Behavioral
Intervention description(s): Participants will be advised on use of a hypocaloric, low carbohydrate diet using lifestyle counseling to include motivational interviewing and problem solving skills training strategies.; Participants will be advised on use of a hypocaloric, moderate low fat diet using lifestyle counseling to include motivational interviewing and problem solving skills training strategies.; Participants will be advised on use of a healthy Mediterranean-based eating plan using lifestyle counseling to include motivational interviewing and problem solving skills training strategies.
Other intervention name(s): Low carbohydrate diet; Low fat diet; Mediterranean diet
Allocation: Randomized
Intervention model: Sequential Assignment
Intervention model description: This initial pilot and feasibility study uses a Sequential, Multiple Assignment, Randomized Trial (SMART) design to identify acceptable and effective dietary strategies to optimize both glycemic control and weight management. The study will be done at UNC and Stanford. Sequential randomization will occur at 0, 3.5, and 7 months. Following the baseline measurement visit and two week run-in period, participants will be randomized to one of three diets (stratified by site with block size of 4). Using a priori decision rules at 3.5 and 7 months post-initial randomization, those for whom the assigned diet is not acceptable or effective will be re-randomized (or re-assigned if only one diet remains untried). 10.5 months of follow-up time allows for evaluation of the effect of diets on initial weight loss and on early maintenance of initial weight loss. Decision criteria for re-randomization will incorporate clinical outcomes (glycemic control and weight change) and acceptability of the diet.
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Type 1 diabetes; T1D; Type 1 diabetes mellitus (T1DM); weight management; overweight; obese