Low EnerGy DiEt iN Adolescents With Obesity and Type 2 Diabetes: The LEGEND Study

Inclusion criteria

• LED intervention
• Diagnosis of T2DM (defined as an HbA1C ≥48mmol/mol, in the absence of features of type 1 or monogenic/syndromic diabetes).
• Current HbA1C ≥48 (or ≥42 on antidiabetic medication) and ≤ 80 mmol/mol. To allow for the day-to-day variation in HbA1C and differences between point of care laboratory tests, -2 or +2 mmol/mol in the HbA1C result will be allowed in the current criteria if one of them is between or equal to 42-80mmol/mol.
• Aged 12 to 17 years old.
• BMI ≥981st centile (+2 SD) for age and sex (UK90 growth reference data).
• Informed consent:
• Received from the young person (age 16-17) OR
• Received from young person's parent/carer, with patient assent (age 12-15).
• Willing to engage in and commit to low energy diet, FR and weight management phases including follow-up and attending study visits.
• LED Intervention Interviews
• The same interview inclusion criteria for LED intervention, with the following additional requirements:
• Patients:
• Informed consent:
• Received from the young person (age 16-17) OR
• Received from young person's parent/carer, with patient assent (age 12-15).
• Willing to take part in a qualitative interview alongside a parent/carer.
• Relative/Carer:
• A relative/carer for a young person meeting the above LED participant eligibility criteria.
• Informed consent from the relative/carer to participate in the interview.
• Willing to take part in a qualitative interview alongside the young person.
• Non-LED Qualitative Interview only participants
• Diagnosis of T2DM (defined as an HbA1C ≥48mmol/mol, in the absence of features of type 1 or monogenic/syndromic diabetes).
• Current HbA1C ≥48 (or ≥42 on antidiabetic medication) and ≤80 mmol/mol.
• Aged 12 to 17 years old.
• BMI ≥91st centile (+2 SD) for age and sex (UK90 growth reference data).
• Informed consent:
• Received from the young person (age 16-17) OR
• Received from young person's parent/carer, with patient assent (age 12-15).
• Willing to take part in a qualitative interview alongside a parent/carer only.
• HCPs
• Registered HCP.
• Experience of delivering this trial to the adolescents.
• Willing to take part in a qualitative interview about undertaking motivational interviewing training and conducting/delivering the LED intervention study.

Exclusion criteria

• LED intervention
• HbA1C greater than 82mmol/mol (to allow for the variation in HbA1c differences).
• Presence of diabetes-related autoantibodies, as per local centre guidelines.
• Confirmed mono-genetic cause of obesity (e.g. SIM1 mutation) or diabetes-associated syndrome such as Prader-Willi syndrome, Bardet-Biedl or Wolfram's syndrome.
• Secondary diabetes (post bone marrow transplant/chemotherapy).
• Significant psychiatric co-morbidity.
• Breastfeeding, pregnant or planning to conceive during the LED and FR phases (female participants will be advised on need for effective contraceptive methods during the 12-month study period, section 5.1.1.10).
• Any other condition which, in the opinion of the study investigator, would make it inappropriate to undertake a period of LED. (All reasons for not approaching patients will be recorded and analysed anonymously. Cases can be discussed with the core study group if there is doubt).
• Participation in another interventional trial within 6 months.
• Informed consent and/or assent not received.
• Pre-existing retinopathy.
• Dietary avoidance (including, but not limited to, due to allergies, intolerances, religious reasons and lifestyle choices) to any ingredients in the meal replacement products, including lactose.
• Previous scoliosis repair.
• Non-LED Qualitative Interview only participants
• HbA1C greater than 80mmol/mol.
• Presence of diabetes-related autoantibodies, as per local centre guidelines.
• Confirmed mono-genetic cause of obesity (e.g. SIM1 mutation) or diabetes-associated syndrome such as Prader-Willi syndrome, Bardet-Biedl or Wolfram's syndrome.
• Secondary diabetes (post bone marrow transplant/chemotherapy).
• Significant psychiatric co-morbidity.
• Breastfeeding, pregnant or planning to conceive during the LED and FR phases (female participants will be advised on need for effective contraceptive methods during the 12-month study period, section 5.1.1.10).
• Any other condition which, in the opinion of the study investigator, would either make it inappropriate to undertake a period of LED. (All reasons for not approaching patients will be recorded and analysed anonymously. Cases can be discussed with the core study group if there is doubt).
• Participation in another interventional trial within 6 months.
• Informed consent and/or assent not received.
• Pre-existing retinopathy.
• Dietary avoidance (including, but not limited to, due to allergies, intolerances, religious reasons and lifestyle choices) to any ingredients in the meal replacement products, including lactose.
• Previous scoliosis repair.
• HCPs
• None.