Table 2: Study characteristics of included studies.

StudyComorbiditiesInclusion criteriaExclusion criteriaPrimary and secondary outcomes

Dixon et al. [13]Hypertension about 28 and 27, metabolic syndrome about 29 and 29, and coronary artery disease about 0 and 1 in the groups gastric banding and medication, respectively.Age 20–60, BMI 30–40 kg/m2, diagnosed type 2 diabetes within the previous 2 years, and no renal impairment or diabetic retinopathy.Type 1 diabetes, diabetes secondary to a specific disease, a history of bariatric surgery, mental impairment, drug or alcohol addiction, recent major vascular event, internal malignancy, portal hypertension, and contraindication.Primary: remission (FBG 126 mg/dL, HbA1c 6.2%, and without the use of oral hypoglycemics or insulin). Secondary: HbA1c, weight, blood pressure, waist circumference, fasting lipids, insulin resistance, adverse events, and changes in medications.

Schauer et al. [14]Hypertension about 35, 30, and 26, metabolic syndrome about 45, 47, and 46, and dyslipidemia about 44, 40, and 36 in the groups gastric bypass, gastrectomy, and medication, respectively.Age 20–60, type 2 diabetes, and BMI 27–43 kg/m2.Undergone previous complex abdominal surgery or had poorly controlled medical or psychiatric disorders.Primary: the proportion of HbA1c 6%. Secondary: FBG, fasting insulin, lipids, CRP, HOMA-IR, weight loss, blood pressure, adverse events, and changes in medications.

Mingrone et al. [15]Not stated.Age 30–60, BMI 35 kg/m2, a history of type 2 diabetes of at least 5 years (HbA1c 7.0%), and an ability to understand and comply with the study protocol.Type 1 diabetes, diabetes secondary to a specific disease or glucocorticoid therapy, previous bariatric surgery, pregnancy, other medical conditions requiring short-term hospitalization, severe diabetes complications, other severe medical conditions, and geographic inaccessibility.Primary: remission (FBG 100 mg/dL, HbA1c 6.5%, and at least 1 year without active pharmacologic therapy). Secondary: FBG, glycated hemoglobin, body weight, waist circumference, arterial blood pressure, plasma cholesterol, HDL cholesterol, and triglycerides.

HbA1c: hemoglobin A1c; BMI: body-mass index. FBG: fasting blood glucose; CRP: high-sensitivity C-reactive protein; HOMA-IR: the homeostasis model assessment of insulin resistance; HDL: high-density lipoprotein.