We performed a meta-analysis of weight loss and remission of type 2 diabetes mellitus (T2DM) evaluated in randomized controlled trials (RCTs) and observational studies of bariatric surgery vs conventional medical therapy. English articles published through June 10, 2013 that compared bariatric surgery with conventional therapy and included T2DM endpoints with ≥12-month follow-up were systematically reviewed. Body mass index (BMI, in kilogram per square meter), glycated hemoglobin (HbA1C, in degree), and fasting plasma glucose (FPG, in milligram per deciliter) were analyzed by calculating weighted mean differences (WMDs) and pooled standardized mean differences and associated 95 % confidence intervals (95 % CI). Aggregated T2DM remission event data were analyzed by calculating the pooled odds ratio (POR) and 95 % CI. Random effects assumptions were applied throughout; I2 ≥ 75.0 % was considered indicative of significant heterogeneity. Systematic review identified 512 articles: 47 duplicates were removed, 446 failed inclusion criteria (i.e., n < 10 per arm, animal studies, reviews, case reports, abstracts, and kin studies). Of 19 eligible articles, two not focused on diagnosed T2DM and one with insufficient T2DM data were excluded. In the final 16 included papers, 3,076 patients (mean BMI, 40.9; age, 47.0; 72.0 % female) underwent bariatric surgery; 3,055 (39.4; 48.6, 69.0 %) received conventional or no weight-loss therapy. In bariatric surgery vs conventional therapy groups, the mean 17.3 ± 5.7 month BMI WMD was 8.3 (7.0, 9.6; p < 0.001; I2 = 91.8), HbA1C was 1.1 (0.6, 1.6; p < 0.001; I2 = 91.9), and FPG, 24.9 (15.9, 33.9; p < 0.001; I2 = 84.8), with significant differences favoring surgery. The overall T2DM remission rate for surgery vs conventional group was 63.5 vs 15.6 % (p < 0.001). The Peto summary POR was 9.8 (6.1, 15.9); inverse variance summary POR was 15.8 (7.9, 31.4). Of the included studies, 94.0 % demonstrated a significant statistical advantage favoring surgery. In a meta-analysis of 16 studies (5 RCTs) with 6,131 patients and mean 17.3-month follow-up, bariatric surgery was significantly more effective than conventional medical therapy in achieving weight loss, HbA1C and FPG reduction, and diabetes remission. The odds of bariatric surgery patients reaching T2DM remission ranged from 9.8 to 15.8 times the odds of patients treated with conventional therapy.Electronic supplementary materialThe online version of this article (doi:10.1007/s11695-013-1160-3) contains supplementary material, which is available to authorized users.

Type 2 diabetes mellitus (T2DM) resolution in morbidly obese patients following metabolic surgery suggests the efficacy of T2DM surgery in non-morbidly obese patients (body mass index [BMI] <35 kg/m(2)). This literature review examined research articles in English over the last 30 years (1979-2009) that addressed surgical resolution of T2DM in patients with a mean BMI <35. Weighted and simple means (95% CI) were calculated to analyze study outcomes. Sixteen studies met inclusion criteria; 343 patients underwent one of eight procedures with 6-216 months follow-up. Patients lost a clinically meaningful, not excessive, amount of weight (from BMI 29.4 to 24.2; -5.1), moving from the overweight into the normal weight category. There were 85.3% patients who were off T2DM medications with fasting plasma glucose approaching normal (105.2 mg/dL, -93.3), and normal glycated hemoglobin, 6% (-2.7). In subgroup comparison, BMI reduction and T2DM resolution were greatest following malabsorptive/restrictive procedures, and in the preoperatively mildly obese (30.0-35.0) vs overweight (25.0-25.9) BMI ranges. Complications were few with low operative mortality (0.29%). Novel and/or known mechanisms of T2DM resolution may be engaged by surgery at a BMI threshold

At 6-month follow-up of a prospective case series, the POSE procedure appeared to provide safe and effective weight loss without the scarring, pain, and recovery issues of open and laparoscopic bariatric surgery. Long-term follow-up and further study are required.

This is the first systematic review and meta-analysis focused exclusively on intermediate-term outcomes for the banded Roux-en-Y gastric bypass (B-RYGB). B-RYGB articles published from 1990 to 2013 were identified through MEDLINE, ScienceDirect, and SpringerLink databases augmented by manual reference review. Articles were assigned an evidence level (Centre for Evidence-Based Medicine [Oxford UK] criteria) and Jadad quality score (randomized controlled trials). Simple and weighted means (95% confidence interval (CI)) for excess weight loss (EWL) at follow-up (1-10+ years) were calculated. At 5 years, a pooled estimate for BMI (kg/m(2)) change (weighted mean difference and 95% CI) for banded bypass patients was computed. Rates for weighted mean complications, non-band- and band-related reoperations, and overall comorbidity resolution were calculated. Three hundred twenty-one articles were identified: 286 failed inclusion criteria (i.e., non-English, B-RYGB unrelated, <10 per arm, <3-year follow-up), leaving 35 articles. Manual review added 10 potentially relevant articles; 30 that failed inclusion criteria were excluded, leaving 15 for analysis. B-RYGB was performed on 8,707 patients: 79.0% female, mean age 38.7, and BMI 47.6 (41.0-59.4). Overall BMI weighted mean difference (reduction) at 5 years was 17.8 (95% CI 12.8, 22.7; p < 0.001). Five-year weighted mean EWL of 72.5% (67.5, 77.4) was sustained at 10+ years (69.4%; 58.9, 80.0). Weighted mean complication rates were as follows: early, 10.9%, and late, 20.0%. Non-band-related reoperation rate was 15.2%, and band-specific reoperation rate was 4.1%. Gastric outlet stenosis, band erosion, and band slippage were 2.8, 2.3, and 1.5%, respectively. Diabetes remitted in 80/95 (84.2%). By systematic review and meta-analysis, albeit with limited rates of follow-up, B-RYGB appeared to result in significant, sustained excess weight loss of approximately 70.0% out to 10 years.

clinicaltrials.gov identifier # NCT01843231.