Table 1.
Effectiveness of bariatric surgery compared with non-surgical management*
| Study | Study details | Weight change | T2DM remission | T2DM incidence | Mortality and survival |
|---|---|---|---|---|---|
| Meta-analysis21 | Meta-analysis of 11 RCTs (n=796); cohorts include RYGB, AGB, BPD, VSG v non-surgical treatments | Bariatric surgery treatment: 1-2 year weight change, mean difference −26 kg, 95% CI −31 to −21; P<0.001 v non-surgical treatment | Bariatric surgery treatment: complete case analysis relative risk 22.1, 3.2 to 154.3; P=0.002; conservative analysis 5.3, 1.8 to 15.8; P=0.003 v non-surgical treatment | Not reported | No cardiovascular events or deaths reported after bariatric surgery or in control populations |
| Swedish Obese Subjects study18 24 | Prospective observational with matched controls (n=2010; 68% VBG, 19% banding, 13 % RYGB); 2037 matched controls | Bariatric surgery treatment: 2, 10, 15, 20 year weight change mean −23%, −17%, −16%, and −18%, respectively; matched control treatment: 2, 10, 15, 20 year weight loss mean 0%, 1%, −1%, and −1%, respectively | Bariatric surgery treatment: 2 years 72% remission (odds ratio for remission: 8.4, 5.7 to 12.5; P<0.001); 10 years 36% durable remission (3.5, 1.6 to 7.3; P<0.001) | Bariatric surgery treatment: 2, 10, and 15 years, reduced risk of developing T2DM by 96%, 84%, and 78%, respectively, in people without the condition at baseline |
Bariatric surgery treatment: 16 years, 29% lower risk of death from any cause (hazard ratio 0.71, 0.54 to 0.92; P=0.01) v usual care; common causes of death: cancer and myocardial infarction |
| Utah Mortality study17 | Retrospective observational with matched controls (7925 RYGB; 7925 weight matched controls) | Not reported | Not reported | Not reported | Bariatric surgery treatment: average 7.1 years post-treatment, 40% (hazard ratio 0.60, 0.45 to 0.67; P<0.001), 49% (0.51, 0.36 to 0.73; P<0.001), and 92% (0.08, 0.01 to 0.47; P=0.005) reduction in all cause mortality, cardiovascular mortality, and T2DM mortality, respectively |
| Utah Obesity study67 | Prospective observational with matched controls; 418 RYGB; 417 bariatric surgery seekers who did not undergo surgery (control 1); 321 population based severely obese matched controls (control 2) | 6 year weight change: −27.7%, +0.2%, and 0% of initial body weight for bariatric surgery, control 1, and control 2, respectively | 6 year remission: 62%, 8%, and 6% for bariatric surgery, control 1, and control 2, respectively | 6 year incident T2DM: 2%, 17%, and 15% for bariatric surgery, control 1, and control 2, respectively | Deaths at 6 years: 12 (2.8%), 14 (3.3%), and 3 (0.93%) for bariatric surgery, control 1, and control 2, respectively |
* AGB=adjustable gastric banding; BPD=biliopancreatic diversion; LABS=Longitudinal Assessment of Bariatric Surgery study; RCT=randomized controlled trial; RYGB=Roux-en-Y gastric bypass; T2DM=type 2 diabetes; VBG=vertical banded gastroplasty; VSG=vertical sleeve gastrectomy.