Major/minor reoperation	Health‐related quality of life	Measures of weight change, fat content or fat distribution	Mortality (perioperative)	Immediate/early/late operative complications	Review's obesity related comorbidities	Revisional surgery	Serious/severe adverse events
Aasheim 2009	N/A	Norwegian and Swedish versions of the Short‐Form‐36 Health Survey (SF‐36) (4‐week recall, version 2.0); obesity‐related Problems scale, score 0 to 100, high score more dysfunction	BMI, BMI reduction, % of excess BMI lost, weight (kg), % of body weight loss, change in weight, waist circumference, hip circumference, sagittal diameter, fat mass (bioelectrical impedance analysis), fat‐free mass (bioelectrical impedance analysis), fat‐free mass (total body potassium measurement), percentage of weight lost as fat‐free mass, percentage of weight lost as fat‐free mass (total body potassium measurement)	Within 30 days of surgery	Perioperative complications = those occurring within 30 days of surgery Late complications = those occurring between 30 days and two years after surgery	Number of participants using antihypertensive drugs, oral hypoglycaemic drugs, insulin and lipid‐lowering therapy with statins. Snoring and sleep apnoea (measured in a sub‐study of participants at one study centre only) were assessed using a questionnaire developed for the study which measured self‐reported snoring and experience of sleep apnoea symptoms	‐	N/A
Angrisani 2007	N/A	N/A	Percentage of excess weight loss, BMI, decrease in BMI, weight (kg), weight loss failure (BMI > 35 kg/m² at 5‐years), BMI < 30 kg/m² at 5 years and 10 years	Any deaths	Early complications = those occurring within 30 days of surgery Late complications reported but not defined.	Resolution of diabetes, sleep apnoea and hyperlipaemia (criteria for resolution not reported)	‐	N/A
Dixon 2008	N/A	N/A	Weight loss (kg), % weight loss, waist circumference, waist to hip ratio	N/A	Complications reported, but not reported as early and late	Proportion of participants achieving remission of type 2 diabetes (fasting plasma glucose <126 mg/dL and HbA1c < 6.2% without the use of oral hypoglycaemic agents or insulin), changes in medication use and in proportion of patients with metabolic syndrome (as defined by the National Cholesterol Education Program Adult Treatment Panel III criteria) Changes in indirect measures of insulin resistance (using homeostatic model assessment method). Remission of type 2 diabetes, metabolic syndrome (number and proportion NOT meeting criteria), HbA1c, proportion with HbA1c <6.2%, systolic blood pressure, diastolic blood pressure, plasma glucose, plasma insulin, total cholesterol, triglycerides, HDL‐C, total cholesterol to HDL‐C ratio, use of diabetes medication, use of non diabetes medication (antihypertensive agents, lipid‐lowering agents)	‐	‐
Demerdash 2013	N/A	N/A	BMI, % body weight decrease	N/A	N/A	‐	N/A	N/A
Dixon 2012	N/A	SF‐36 (domain scores and component summary scores)	Weight (kg), weight loss (kg), % weight loss, BMI, BMI loss, waist circumference, change in waist circumference, neck circumference, change in neck circumference	N/A	Complications reported, but not reported as early and late	Achieved mild obstructive sleep apnoea (OSA) (apnoea‐hypopnoea index [AHI] < 15 events/hour), achieved OSA remission (AHI < 5 events/hour), metabolic syndrome status	N/A	Those requiring urgent hospitalisation
Hedberg 2012	N/A	N/A	BMI, % excess BMI lost, failure to achieve > 50% of excess BMI loss. Weight at ≥ 24 mo measured in a self‐report patient questionnaire	Perioperative period not defined	Perioperative and late complications reported, but measurement period not defined. Some adverse events were measured by a self‐report participant symptom questionnaire and were not reported in the publication (reported: diarrhoea, malodorous flatus, reoperations and revisional surgery; not reported: abdominal pain, abdominal symptoms 'extended enquiry', dumping, heartburn, soiling, vomiting)	Medication use (not reported), proportion of patients with HbA1c < 5%	‐	N/A
Himpens 2006	N/A	N/A	Weight loss (kg), BMI, % excess weight loss	N/A	Complications not defined as immediate/early/late Complications reported as 'not requiring surgery' and 'requiring surgery'	Modification of gastroesophageal reflux disease (GERD) (number of patients on proton pump inhibitor (PPI) medication)	‐	N/A
Ikramuddin 2013	N/A	N/A	Waist circumference (cm), weight (kg), BMI, percent weight change	N/A	Complications were reported as postoperative and late surgical but the time periods were not defined explicitly; the postoperative complications were also referred to as 'perioperative' and appear to have occurred early in the post‐operative period	Composite comorbidity endpoint defined as HbA1c < 7.0%, LDL‐C < 100 mg/dL, and systolic blood pressure < 130 mm Hg, at the 12‐month visit; number of medications used to control glycaemia, dyslipidaemia and blood pressure; n and % of participants with HbA1c < 6.0% and n and % of participants with fasting glucose < 100 mg/dL	Reported but not defined explicitly (unclear whether all cases of revision reported)	Reported but not defined explicitly
Karamanakos 2008	N/A	N/A	% excess weight loss, BMI, achieved >50% of excess weight lost	N/A	Perioperative/early morbidity (≤ 30 days), late morbidity	Resolution or improvement of preoperative comorbidities (n and %): hypertension (systolic blood pressure ≥140 and/or diastolic blood pressure ≥90 mm Hg or antihypertensive drug therapy), type 2 diabetes mellitus (fasting plasma glucose ≥126 mg/dL or 2‐h plasma glucose ≥200 mg/dL during OGTT or antidiabetic drug with or without insulin therapy), impaired glucose tolerance (2‐h plasma glucose ≥140 mg/dL and ≤200 mg/dL during oral glucose tolerance test (OGTT)), HDL < threshold (<40 mg/dL for men, <50 mg/dL for women), LDL > threshold (>100 mg/dL), triglycerides > threshold (> 150), obstructive sleep apnoea (repeated episodes of upper airway occlusion during sleep, with or without sleepiness, and high apnoea‐hypopnoea index and need for nasal continuous positive airway pressure during sleep), GERD (need for PPI agents and/or oesophagitis revealed on endoscopy), degenerative arthritis (clinical and radiological documentation), menstrual irregularities (clinical and/or hormonal documentation)	‐	Major complications reported, but not defined
Keider 2013	N/A	N/A	Weight, BMI, body fat (%), fat mass (kg), fat‐free mass (kg), Waist (cm)	Period not defined	N/A	HBA1c (% and mmol/mol); diabetes treatments (oral, insulin, diet), 'off glucose lowering medications', 'normal fasting glucose and HbA1c', 'impaired fasting glucose with normal HbA1c' (no further details provided for these three outcomes)	‐	‐
Lee 2011	N/A	N/A	% weight loss, BMI, weight (kg), % excess weight loss, waist circumference	N/A	An early complication was defined as a complication that occurred ≤ 30 days post‐surgery A late complication was defined as a complication that occurred > 30 days post‐surgery or required re‐admission	Glycaemic control (defined as the proportion of patients achieving remission of type 2 diabetes, defined as a fasting plasma glucose level of < 126 mg/dL, plus a HbA1c level of < 6.5% without the use of oral hypoglycaemics or insulin), successful treatment of diabetes mellitus (defined as HbA1c < 7%, LDL‐C < 100 mg/dL, and triglycerides < 150 mg/dL), metabolic syndrome (defined by the National Cholesterol Education Program Adult Treatment Panel III criteria), changes in medication use	N/A	A major complication was defined as a complication requiring intervention and hospitalisation for more than 14 days.
Liang 2013	N/A	N/A	Weight and BMI measured using the International Collaborative Study on Hypertension in Blacks (ICSHIB) standardised protocol	N/A	Adverse events were measured but not defined as early or late	Type 2 diabetes resolution (not defined); discontinuation of diabetes and hypertension drugs; presence of hypertension; hypertension defined as systolic blood pressure 140 mmHg and/or diastolic (DBP) 90 mmHg as per 1999 WHO/ISH criteria	N/A	A serious adverse event was defined as an adverse event that resulted in death, hospitalisation, disability, life‐threatening experience, or that required medical or surgical intervention to prevent one of the other outcomes
Mingrone 2012	N/A	N/A	% weight loss, % excess weight loss, BMI, BMI change, waist circumference	N/A	Late complications reported, but not defined	Rate of remission of type 2 diabetes (a fasting plasma glucose level of < 100 mg/dL (5.6 mmol/L and a HbA1c level of < 6.5% for at least 1 year without active pharmacologic therapy (based on recommendations by the American Diabetes Association)), discontinuation of pharmacological treatment for diabetes, total cholesterol normalisation (not defined), HDL cholesterol normalisation (not defined), LDL cholesterol normalisation (not defined), triglyceride normalisation (not defined), reduction/discontinuation of antihypertensive therapy	N/A	‐
Nguyen 2009	N/A	SF‐36 (operationalised as the number of domains with improved scores, and the number of domains with scores comparable to US norms; criteria for defining improvement in scores was not reported)	Excess weight lost (EWL) (pre‐operative weight minus post‐operative weight, divided by pre‐operative weight minus ideal body weight and multiplied by 100), weight loss was also categorized into 5 groups according to the % EWL: poor/failure (<20%), acceptable (20%–39.9%), good (40%–59.9%), excellent (60%–79.9%), and exceptional (≥80%), BMI, treatment failure (defined as (1) the need for conversion to another bariatric procedure due to failure of weight loss or (2) having <20% EWL)	In hospital or within 30 days of surgery	Early complications (≤ 30 days after surgery) Late complications (> 30 days after surgery)	N/A	‐	Complications were graded as follows: surgical complications grade I (alterations from the ideal postoperative course, non‐life‐threatening, and with no lasting disability), grade II (potentially life‐threatening but without residual disability, subdivided in to 2 groups: IIa, requiring blood transfusions, total parenteral nutrition, drug therapy, or a hospital stay twice the median stay; and IIb, requiring therapeutic procedures such as endoscopy or reoperation), grade III (with residual disability or requiring organ resection), grade IV (death). Major complications were defined as grade IIb, III, IV complications.
Nogues 2010	N/A	N/A	Weight (kg), weight change, BMI, BMI change	N/A	Complications during and after surgery reported, but measurement periods not defined	Normalisation of insulin resistance (HOMA‐IR) in participants who fulfilled criteria for insulin resistance at baseline; withdrawal of use of diabetic medication at 3 months among a subgroup of patients with diabetes at baseline	N/A	N/A
O'Brien 2006	N/A	SF‐36 (domain scores)	Change in absolute weight (kg), body mass index, percentage of initial weight lost and excess weight lost, proportion of patients losing more than 50% of excess weight, proportion of patients achieving satisfactory weight loss (greater than 25% of excess weight lost)	N/A	Total events reported, not reported as early or late	Number and proportion of patients with metabolic syndrome (defined by the Adult Treatment Panel III criteria)	‐	Major complications were defined as those that required hospitalisation or major outpatient treatment (major events were defined but not reported; only total and specific events reported)
Paluszkiewicz 2012	N/A	N/A	BMI, weight (kg), % EWL, %EWL > 50%. Excess weight was defined as initial body weight in excess of the upper limit of the normal weight ranges estimated at the BMI of 25 kg/m² for a given participant height	≤ 30 d	Early complications (< 30 day) Late complications (> 30 day)	Number and proportion of patients with remission or improvement in comorbidities. Hypertension, change from baseline in hypertension, type 2 diabetes, change from baseline in type 2 diabetes, dyslipidaemia, change from baseline in dyslipidaemia. Remission of co‐morbidities assessed according to the clinical, biochemical, hormonal and radiological documentation. Improvement defined as a reduction of medication taken and improvement of the symptoms or blood investigation specific to the comorbidity. Remission of hypertension: normal systolic and diastolic arterial pressure without active antihypertensive treatment. Remission of type 2 diabetes: normal fasting glucose levels (<100 mg/dL) and HbA1c < 6% in the absence of active antidiabetic treatment. Remission of dyslipidaemia: normal levels of total cholesterol, triglycerides, HDL cholesterol and LDL cholesterol in the absence of active lipid‐lowering treatment	‐	A major complication was defined as a complication resulting in death or reoperation, a hospital stay of more than 7 days after the procedure, or a need for blood transfusion of four or more units
Peterli 2012	N/A	Gastrointestinal Quality of Life Index (GIQLI) questionnaire score, BAROS‐QoL score (only reported for a subgroup of participants as not all study centres returned these data)	Weight (kg), BMI, % excess BMI loss	Within 30 days of surgery	Perioperative complications (within 30 d surgery)	Discontinuation of medication for type 2 diabetes, new‐onset GERD. Proportion of patients with remission or improvement of comorbidities, including hypertension, diabetes mellitus type 2, dyslipidaemia, obstructive sleep apnoea syndrome, back/joint pain, hyperuricaemia, GERD and depression. "Remission and improvement of comorbidities were defined by the endocrinologist/physician responsible for follow‐up"	‐	Perioperative complications were graded using the Clavien/Dindo grading system: Grade I complications are defined as minor deteriorations from the normal postoperative course, grade II complications require treatment by drugs, blood transfusion, physiotherapy or nutritional support, grade III complications need interventional or operative treatment, grade IV complications are life‐threatening and managed by ICU, and grade V is death.
Praveen Raj 2012	N/A	N/A	BMI, excess weight loss (kilograms), percent excess weight loss	N/A	Complications reported, unclear at which time points complications were measured (only one complication was reported and this occurred at 1 mo)	Improvement in type 2 diabetes mellitus (DM), among a subsample with DM at baseline, improvement in hypertension among a subsample with hypertension at baseline, lipid profile. Remission of DM defined as achieving a HbA1C of < 7 without the need for oral hypoglycaemic agents (OHA) or insulin. ‘Improvement’ did not appear to be pre‐defined, and was characterised slightly differently for each arm in the results. Remission of hypertension (no requirement of medication by one year), improvement of hypertension (reduced requirement of medication), lipid profile (normalisation of all parameters)	‐	N/A
Schauer 2012	N/A	N/A	Weight (kg), change in weight, BMI, change in BMI, % excess weight loss, waist circumference, waist‐ hip ratio	N/A	Adverse events reported up to 12 months, but not defined as early or late	Proportion of patients with an HbA1c level of 6% or less (with or without diabetes medications), coexisting illnesses, changes in medication, HbA1c categorisation, resolution of metabolic syndrome	‐	Serious adverse events reported but not defined
Sharma 2013	N/A	N/A	BMI and EWL	N/A	Two major complications reported but not explicitly defined (however, they both required reoperations)	N/A	Not defined in study, but trial reported that two reoperations were required in gastric imbrication group. A gastric outlet obstruction was revised by a removal of the sutures that were blocking the outflow of the pouch. A leak was reoperated on and converted to a sleeve gastrectomy	N/A
Vix 2013	N/A	N/A	%EWL	N/A	N/A	N/A	N/A	N/A
"‐" denotes not reported BMI: body mass index; d: day(s); EWL: excess weight lost; GERD: gastroesophageal reflux disease; HbA1c: glycosylated haemoglobin A1c; HDL(‐C): high density lipoprotein (cholesterol); ICU: intensive care unit; ISH: International Society of Hypertension; LDL(‐C): low density lipoprotein (cholesterol); mo: month(s); N/A: not applicable; OGTT: oral glucose tolerance test; PPI: proton pump inhibitor; WHO: World Health Organization