Randomized Clinical Trial; Medical vs Bariatric Surgery for Adolescents (13-16 y) With Severe Obesity (AMOS2)

AMOS2 (Adolescent Morbid Obesity Surgery)

Severe childhood obesity is associated with both immediate and chronic health problems and a severe impact on psychosocial development. Medical and behavioural interventions rarely result in the significant, durable weight loss necessary to improve health outcomes.

This is a randomised clinical trial where 50 adolescents, 13-16 years of age, will be randomised to either early bariatric surgery (Roux-en-Y gastric bypass) or intense conservative treatment and possibly surgery after two years of non-surgical treatment or as they have become 18 years.

Study Overview

• Status: Active, not recruiting
• Conditions: Inflammation; Hypertension; Obesity; Diabetes; Steatohepatitis
• Intervention / Treatment: Procedure: Laparoscopic Roux-en-Y gastric bypass; Procedure: Intense conservative treatment

Detailed Description

A multicentre randomised clinical trial where three tertiary referral hospitals recruit patients.

Patients and their parents receive information about the study at their paediatric clinic and at the trial web page (www.amos2.se). Standardised procedure, including signed informed consent.

Interventions

At the end of day of baseline examination patients are randomised to either of two arms:

• Bariatric surgery with regular follow up
• Optimised conservative treatment starting with an 8-week Low Calorie Diet period followed by tailored support and treatment by the multidisciplinary team with an intensity of at least one visits a month over at least 2 years

Patients in the conservative arm will be reassessed regarding interest of undergoing bariatric surgery two years after inclusion.

Sample Size A sample size of 50 (25+25) leaves a power of more than 95% to evaluate a possible superiority of >10% weight difference between the two groups, assuming a 15% standard deviation in weight loss over follow-up at 2.5% significance level.

This number also allows assessment for differences in cardiovascular risk factors with sufficient power and acceptable power for demonstrating differences in quality of life and cognitive functions.

3.6 Randomization The computerized random allocation is performed during the day of baseline examination and patients were informed of their assignment. Forty-nine patients have been included until May 2017, and the last patient will be operated on June 14th. Stratification has been performed according to the recruitment centre

3.8 Statistical Methods & Additional Analyses Safety & Efficacy Outcomes: Analyses will be by intention to treat, including all randomised patients. Difference in treatment effect will be evaluated with hazard ratio between the treatment groups, and the corresponding confidence interval will be calculated. For secondary outcomes, the incidence of comorbidities during follow-up will be evaluated using time-to-event models, and for continuous variables mixed models will be used to evaluate differences between the treatment groups.

Incremental cost-effectiveness analysis will be conducted by calculating the incremental cost-effectiveness ratio (ICER; dividing the between-group difference in costs with the between-group difference in quality-adjusted life-years (QALYs) as well as life-years). Probabilistic sensitivity analysis will be conducted and results presented in an ICER scatterplot and cost-effectiveness acceptability curve.

Follow-Up Clinical Data Collection: Study point are 6 weeks, 1 year, 2 years, and 5 years after the start of intervention. Weight, quality of life, and adverse events, as well as clinical data regarding treatments for co-morbidities. Blood sampling for assessment of nutritional deficiencies, glucose control, blood lipids and inflammation will be collected at baseline and 1, 2 and 5 years.

Cognitive functions: Assessments will be performed at baseline and 1 and 2 years after start of intervention.

Register-Based Data Collection and Health-Economic Outcomes: Collection and analysis of Swedish national health care and other official registries

We decided in the Study Steering Committee to change time points for long term follow up to be 5, 10 and 15 years after treatment initiation to better comply with standard schedules for clinical follow up in registers (instead of 7, 12 and 17y after treatment initiation).

• Study Type: Interventional
• Enrollment (Actual): 50
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Sweden
  • Gothenburg, Sweden, 41345
    • Sahlgrenska University Hospital
  • Malmö, Sweden
    • Skane University Hospital
  • Stockholm, Sweden
    • Karolinska University Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 13 years to 16 years (CHILD)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Age 13-16 years
• BMI >35
• Failed comprehensive treatment for obesity > 1 year
• Passing assessment of psychologist
• Tanner 3 or more

Exclusion Criteria:

• Monogenic obesity (for example Prader Willis, Laurence Moon-Bardet-Biedl)
• Obesity secondary to brain injury
• Severely mentally disabled
• Not eligible for general anesthesia
• Psychotic or other major psychiatric illness
• Previous major gastrointestinal surgery

Study Plan

How is the study designed?

Design Details

• Primary Purpose: TREATMENT
• Allocation: RANDOMIZED
• Interventional Model: PARALLEL
• Masking: NONE

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
EXPERIMENTAL: Bariatric surgery; Roux-en-Y gastric bypass surgery	Procedure: Laparoscopic Roux-en-Y gastric bypass; Bariatric surgery with Roux-en-Y gastric bypass as preferred option, possible laparoscopic Vertical Sleeve Gastrectomy
ACTIVE_COMPARATOR: Intense conservative treatment; Intense conservative treatment. 8 week LCD followed by outpatient visits 1/ month	Procedure: Intense conservative treatment; Intense medical treatment for obesity (behavioral treatment, dietary intervention, exercise, medication etc) 8 week period of Low Calorie Diet. Treatment intensity about 1 visit a month over 2 years

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Body Mass Index (kg/m2)	2 years after treatment initiation

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Metabolic control	Glucose control (fP-Glc, fs-Insulin, HbA1c, Oral glucose tolerance test), Blood lipids (HDL, LDL, TG, Apo A, Apo B), Blood pressure (systolic and diastolic), Inflammation (LPK, CRP, Adiponectin, IL-6, TNF-alfa), liver function tests (AST, ALT, ALP, Bil)	2, 5, 10 and 15 years after treatment initiation
Quality of life, generic	Mental and physical quality of life assessed by Short Form-36 (score 0-100, lower= more disability)	2, 5, 10 and 15 years after treatment initiation
Obesity-specific quality of life	Obesity Problem scale- 9 items (score 0-100, higher score= more psychosocial impairment)	2, 5, 10 and 15 years after treatment initiation
Socioeconomic development	Education, civil status, number of children, income, sick leave (from national registries)	5, 10 and 15 years after treatment initiation
Health care consumption	In hospital care, outpatient care, prescribed medications; from national registries	2, 5, 10 and 15 years after treatment initiation
Skeletal maturation and quality	Bone mineral content and bone mineral density will be assessed as well as blood markers for bone formation and resorption	2, 5, 10 and 15 years after treatment initiation
Addictive behavior	Alcohol consumption, blood markers for alcohol consumption, drugs, brain response to visual stimuli	2, 5, 10, 15 years after treatment initiation
Mental health	Depression, anxiety, self esteem, stability in neuropsychiatric disease (ADHD, ADD), psychiatric illness, OCD	2, 5, 10 and 15 years after treatment initiation
Adverse events	Any adverse event (physical, mental or other)	2, 5, 10 and 15 years after treatment initiation
Eating function	Assessment of meal pattern, dietary composition and gastrointestinal symptoms in relation to eating	2, 5, 10 and 15 years after treatment initiation
Energy expenditure	Doubly labelled water, basic metabolic rate, 24h energy expenditure chamber 5 years	5 years after treatment initiation
Body Mass Index, body weight, height. Additional assessments of primary outcome	Weight (kg) and height (m) will be combined to report BMI in kg/m2	5, 10 and 15 years after treatment initiation
Cognitive Function	General cognitive functioning (IQ test- WISC-IV Wechsler Intelligence Scale for Children) Scale 1-200 where lower score means worse)	1, 2 and 5 years after treatment initiation
Working memory	Memory (D-KEFS-Delis-Kaplan Executive Function System) several subscales 0-15, lower value means worse	1, 2 and 5 years after treatment initiation
Attention	Attention (NEPSY- NEuroPSYcologic examination). Separate subscales for executive function and attention, language, memory and learning, sensorimotor, visuospatial processing, and social perception. Lower value means worse.	1, 2 and 5 years after treatment initiation

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cancer or precancerous lesions	As this parameter is hard to foresee we might need to extend the time for assessment longer than 15 years	15 years after treatment initiation and later

Collaborators and Investigators

• Sponsor: Göteborg University
• Collaborators: Karolinska University Hospital; Lund University; Sahlgrenska University Hospital, Sweden
• Investigators: Principal Investigator: Torsten Olbers, MD, PhD, University of Gothenburg, Dept of Surgical Sciences

Publications and helpful links

General Publications

• Janson A, Jarvholm K, Gronowitz E, Sjogren L, Klaesson S, Engstrom M, Peltonen M, Ekbom K, Dahlgren J, Olbers T. A randomized controlled trial comparing intensive non-surgical treatment with bariatric surgery in adolescents aged 13-16 years (AMOS2): Rationale, study design, and patient recruitment. Contemp Clin Trials Commun. 2020 Jun 27;19:100592. doi: 10.1016/j.conctc.2020.100592. eCollection 2020 Sep. Erratum In: Contemp Clin Trials Commun. 2020 Dec 10;20:100690.

Study record dates

Study Major Dates

• Study Start (ACTUAL): August 15, 2014
• Primary Completion (ANTICIPATED): June 1, 2022
• Study Completion (ANTICIPATED): June 1, 2034

Study Registration Dates

• First Submitted: August 26, 2014
• First Submitted That Met QC Criteria: March 3, 2015
• First Posted (ESTIMATE): March 4, 2015

Study Record Updates

• Last Update Posted (ACTUAL): March 25, 2022
• Last Update Submitted That Met QC Criteria: March 24, 2022
• Last Verified: March 1, 2022

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Digestive System Diseases; Pathologic Processes; Liver Diseases; Overnutrition; Nutrition Disorders; Overweight; Body Weight; Obesity; Inflammation; Fatty Liver
• Other Study ID Numbers: 578-13