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

Phase 4RecruitingNCT05744479

Centre for Addiction and Mental Health100 enrolled

Overview

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.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

QUADRUPLE

Enrollment

100

Conditions

Intellectual Disability

Interventions

MetforminDRUG

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

PlaceboDRUG

Oral placebo for 24 weeks

Lifestyle InterventionBEHAVIORAL

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.

Eligibility

Sex: ALLMin age: 16 YearsMax age: 65 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Stable outpatients * Age 16-65 years * Diagnosed with an IDD * On maintenance treatment with an antipsychotic (stable dose for ≥3 months). * BMI must be ≥30 kg/m2, OR ≥27 kg/m2 with at least one weight-related comorbidity (treated or untreated) such as: hypertension, dyslipidaemia, obstructive sleep apnea, or impaired fasting glucose, OR \>=25 for individuals who have gained \> 5% body weight in association with AP use. * Females of child-bearing age must be on one of the following regular contraceptives: 1. Agree to abstain from sex for the duration of the trial or 2. A barrier method of a diaphragm with spermicide and/or Latex condom or 3. An oral contraceptive agent, implantable contraceptive or an injectable contraceptive for at least six months prior to entering the study and will continue its use throughout the study, or 4. An intrauterine device, or 5. Partner has had a vasectomy at least 3 months prior to study start Exclusion Criteria: * 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% * History of metabolic acidosis or lactic acidosis * Treatment with weight-lowering agents * Medications with significant renal impact * Major medical or surgical event in the preceding 3 months * Acute suicidal risk. * Moderate to severe substance use disorder, other than caffein or nicotine use disorder

Outcomes

Primary Outcomes

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

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

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

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

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

Change in whole body insulin sensitivity calculated with Matsuda Index

With the results of the oral glucose tolerance test at Week 0 and Week 24, insulin sensitivity was calculated with the Matsuda index. Insulin sensitivity was calculated with Matsuda index: \[10,000 / √glucose minute 0 x insulin minute 0) (mean glucose (OGTT) x mean insulin OGTT)\]. A higher result is better. In the formula OGTT: oral glucose tolerance test.