Metformin for Antipsychotic-induced Weight Gain in Adults With Intellectual Disability

Trial statusRecruiting
Trial phasePhase 4
Trial typeInterventional
Biological sexAll
Age16-65
SponsorCentre for Addiction and Mental Health

About this trial

People with IDD (intellectual and developmental disability) have very high rates of obesity and die prematurely from cardiometabolic disease. While antipsychotics contribute to this problem, their use is necessary and appropriate in a significant subgroup of individuals with IDD. Exercise and diet interventions have limitations and may not be sufficient, requiring effective adjunctive pharmacological approaches to target obesity and related comorbidities in IDD. However, persons with IDD treated with antipsychotics are systematically excluded from clinical trials hindering development of evidence to help guide safe and effective treatment of these comorbidities. Moreover, evidence from other disorders cannot be extrapolated to IDD given inherent biological differences between disorders. This trial will address the identified gaps, which extend beyond cardiovascular morbidity and negatively impact psychosocial outcomes, in a hugely underserviced population.This is the the first RCT (randomized control trial) to examine the efficacy of metformin in overweight or obese adults with IDD who have experienced antipsychotic-induced weight gain. By generating efficacy data for a very accessible and scalable intervention, allows for guideline and implementation strategies to address a recalcitrant health problem.

Eligibility criteria

This trial does not accept healthy volunteers

Qualifiers

Stable outpatients

Age 16-65 years

Diagnosed with an IDD

On maintenance treatment with an antipsychotic (stable dose for ≥3 months).

Disqualifiers

Females who are nursing, currently pregnant, or have a positive pregnancy test

Clinical or laboratory evidence of uncompensated cardiovascular, endocrine, haematological, hepatic, renal, or pulmonary disease

Previous treatment and lack of efficacy or tolerability with metformin

History or diagnosis of Type 1 Diabetes (T1D) or Type 2 Diabetes (TD2) or fasting blood work, HbA1c > 6.5%

Trial design

Design model

Parallel

Treatments tested in this trial

  • Metformin

    Drug

    Metformin oral, 2000mg/day, for 24 weeks.

  • Placebo

    Drug

    Oral placebo for 24 weeks

  • Lifestyle Intervention

    Behavioral

    Participants from both groups will meet a dietician and a diabetes educator at the study start to obtain advice regarding healthy diet, portion size, and meal planning to improve physical health. All participants will be invited to monthly group meetings to learn skills which will help them in a variety of wellness areas such as physical exercises and diet. Attendance in these sessions will be encouraged but not mandatory, and attendance will be recorded. Fidelity with these interventions will be captured using diet and physical activity questionnaires at RCT start, midpoint and end, and end of open label phase.

Treatment groups

100 Participants
are divided into 2 treatment groups
Group A: Metformin (Oral)Experimental treatment 2 interventions
Group B: PlaceboPlacebo comparator 2 interventions

Trial outcomes

Primary outcomes

1

Individual's percentage change in body weight

Percentage change in body weight measured in percentage change of pounds (lbs)

Time frame
Weeks 0, 4, 8, 12, 16, 10, 24

Secondary outcomes

1

Proportion of participants who achieve body weight reduction ≥5%, and ≥10% in each arm

Percentage change in body weight measured in percentage change of pounds (lbs), expressed as a percentage

Time frame
Week 0 and week 24
2

Between group (metformin vs placebo) absolute change in weight

Absolute change in body weight between metformin and placebo groups measured in pounds (lbs). Calculated by the mean change in weight between the metformin and placebo groups.

Time frame
Week 24
3

Between group absolute change in waist circumference

Absolute change in waist circumstance measured in centimetres (cm) between metformin and placebo groups. Calculated by the mean change in waist circumstance between the metformin and placebo groups.

Time frame
Week 24
4

Between group absolute change in BMI

Absolute change in BMI between metformin and placebo groups. Calculated by the mean change in BMI between the metformin and placebo groups.

Time frame
Week 24

Other outcomes

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