Outcome
Type |
Measure |
Description |
Time frame |
Safety issue |
Primary |
Change in liver fat content |
Change in liver fat content as measured on MRI scan +/- fibroscan |
Baseline measurement just prior to initiation of routine preoperative low calorie diet (this starts 3-4 weeks before surgery) compared to measurements on completion of this (within a week of surgery) and at 20% weight loss and 1 year after SG or RYGB |
|
Secondary |
Hepatic fatty acid synthesis |
measured by incorporation of 2H2 palmitate from 2H2O into very low density lipoprotein triglyceride (VLDL-TG) and contribution of de novo lipogenesis and uptake and re-esterification to the hepatic triglyceride pool in liver biopsy |
liver biopsy taken during SG or RYGB |
|
Secondary |
Changes in relative contributions of pathways involved in lipid homeostasis |
measured using mathematical modelling of results from stable isotope mixed meal test |
Baseline measurement just prior to initiation of routine preoperative low calorie diet (this starts 3-4 weeks before surgery) compared to measurements on completion of this (within a week of surgery) and at 20% weight loss and 1 year after SG or RYGB |
|
Secondary |
Changes in fasting and postprandial plasma lipid concentration |
measured using a clinical analyser (in fasting states and in response to mixed meal test) |
Baseline measurements just prior to initiation of routine preoperative low calorie diet (this starts 3-4 weeks before surgery) compared to measurements on completion of this (within a week of surgery) and at 20% weight loss and 1 year after SG or RYGB |
|
Secondary |
Changes in fasting and postprandial plasma glucose concentration |
measured using a clinical analyser measured using a clinical analyser (in fasting state and in response to mixed meal test) |
Baseline measurement just prior to initiation of routine preoperative low calorie diet (this starts 3-4 weeks before surgery) compared to measurements on completion of this (within a week of surgery) and at 20% weight loss and 1 year after SG or RYGB |
|
Secondary |
Change in the incorporation of 13C (from dietary fat) into CO2 |
measured using a breath analyser (in fasting state and in response to mixed meal test) |
Baseline measurement just prior to initiation of routine preoperative low calorie diet (this starts 3-4 weeks before surgery) compared to measurements on completion of this (within a week of surgery) and at 20% weight loss and 1 year after SG or RYGB |
|
Secondary |
Expression changes (gene/protein) in adipose tissue biopsies |
measured using techniques such as quantitative real-time PCR (polymerase chain reaction) and ELISA (enzyme- linked immunosorbent assay) |
Baseline measurement just prior to initiation of routine preoperative low calorie diet (this starts 3-4 weeks before surgery) compared to measurements on completion of this (within a week of surgery) and at 20% weight loss and 1 year after SG or RYGB |
|
Secondary |
Change in fat mass |
Proportional (% relative to baseline and lean mass) and absolute changes measured using DXA scan and bioimpedence analysis |
Baseline measurement just prior to initiation of routine preoperative low calorie diet (this starts 3-4 weeks before surgery) compared to measurements on completion of this (within a week of surgery) and at 20% weight loss and 1 year after SG or RYGB |
|
Secondary |
Change in lean mass |
Proportional (% relative to baseline and fat mass) and absolute changes measured using DXA scan and bioimpedence analysis |
Baseline measurement just prior to initiation of routine preoperative low calorie diet (this starts 3-4 weeks before surgery) compared to measurements on completion of this (within a week of surgery) and at 20% weight loss and 1 year after SG or RYGB |
|
Secondary |
Change in functional strength |
measured using hand dynamometer |
Baseline measurement just prior to initiation of routine preoperative low calorie diet (this starts 3-4 weeks before surgery) compared to measurements on completion of this (within a week of surgery) and at 20% weight loss and 1 year after SG or RYGB |
|
Secondary |
changes in fasting and post-prandial peptides/proteins (e.g. PYY, GLP-1, insulin) |
measured using ELISA (in fasting state and in response to mixed meal test) |
Baseline measurement just prior to initiation of routine preoperative low calorie diet (this starts 3-4 weeks before surgery) compared to measurements on completion of this (within a week of surgery) and at 20% weight loss and 1 year after SG or RYGB |
|
Secondary |
change in weight |
measured in kilograms using weighing scales |
Baseline measurement just prior to initiation of routine preoperative low calorie diet (this starts 3-4 weeks before surgery) compared to measurements on completion of this (within a week of surgery) and at 20% weight loss and 1 year after SG or RYGB |
|
Secondary |
change in body mass index (BMI) |
weight measured in kilograms using weighing scales and combined with height in metres to report BMI in kg/m^2 |
Baseline measurement just prior to initiation of routine preoperative low calorie diet (this starts 3-4 weeks before surgery) compared to measurements on completion of this (within a week of surgery) and at 20% weight loss and 1 year after SG or RYGB |
|
Secondary |
change in status of metabolic diseases (e.g. diabetes) / metabolic disease risk scores |
measured with blood tests (e.g. hba1c), by recording clinical changes including medication requirements and clinical data (e.g. blood pressure) |
Baseline measurement just prior to initiation of routine preoperative low calorie diet (this starts 3-4 weeks before surgery) compared to measurements on completion of this (within a week of surgery) and at 20% weight loss and 1 year after SG or RYGB |
|
Secondary |
complications, re-operation, mortality |
clinical events will be recorded |
Baseline measurement just prior to initiation of routine preoperative low calorie diet (this starts 3-4 weeks before surgery) compared to measurements on completion of this (within a week of surgery) and at 20% weight loss and 1 year after SG or RYGB |
|
Secondary |
changes in subcutaneous, visceral and pancreatic fat |
measured on MRI scan |
Baseline measurement just prior to initiation of routine preoperative low calorie diet (this starts 3-4 weeks before surgery) compared to measurements on completion of this (within a week of surgery) and at 20% weight loss and 1 year after SG or RYGB |
|