observational studies and small - randomized trials have shown improvement in patients with diabetes mellitus after bariatric surgery . the stampede ( surgical treatment and medications potentially eradicate diabetes efficiently ) trial 
  is , to - date , the largest randomized trial and has the longest follow - up . a single - center study that randomized patients with uncontrolled type 2 diabetes mellitus ( and obesity ) to either intensive medical therapy , or medical therapy following sleeve gastrectomy , or gastric bypass . a 12-month follow - up was initially reported in the in the new england journal of medicine in 2012 , 
  and more recently , the 3-year outcome was simultaneously presented at the 63 annual scientific session of the american college of cardiology in washington , dc , usa and published in the new england journal of medicine . eligibility criteria included an age of 20 to 60 years , a glycated hemoglobin level of more than 7% , and a body - mass index ( bmi , the weight in kilograms divided by the square the height in meters ) of 27 to 43 . patients were randomized in a 1:1:1 ratio , to one of the three study groups ; intensive medication therapy , gastric bypass or sleeve gastrectomy . patients were followed - up for 3 years and the primary outcome was a glycated hemoglobin level of   6% , with or without the use of diabetes mellitus medications . secondary endpoints included levels of fasting plasma glucose , fasting insulin , lipids , and high - sensitivity c - reactive protein ( crp ) , weight loss , blood pressure , adverse events and changes in medications . nine patients withdraw from the trial immediately after randomization or during the initial 6 months ( 8 patients in the medical - therapy group and 1 patient who did not undergo sleeve gastrectomy because of severe anemia ) ; 4 patients were lost to follow - up . the remaining 137 patients ( 91.3% ) were evaluated in the 3-year assessment of safety and efficacy . the mean (    sd ) was 48    8 years and the mean bmi was 36.5    3.5 , 68% were women and 74% were white . the mean glycated hemoglobin was 9.3    1.5% , and the average duration of diabetes was 8.3    5.1 years , with 43% requiring insulin at baseline . there were no significant differences between the study groups at baseline . at 3 years , the targeted hba1c   6% was achieved in 5% of patients in the medical therapy group compared to 38% of those in the gastric - bypass group ( p  <  0.001 ) and 24% of those in the sleeve - gatsrectomy group ( p  =  0.01 ) . the mean percentage reductions in weight from baseline were greater in the gastric bypass group ( 24.5    9.1% ) and the sleeve - gastretcomy group ( 21.1    8.9% ) , as compared with a reduction of 4.2    8.3% in the medical group ( p  <  0,001 ) . of the patients with baseline albuminuria , a return to normal values at 3 years occurred in 62% in the gastric bypass group , 80% in the sleeve - gastrectomy group and 25% in the medical - therapy group . in regards to quality of life , there were significant improvements in five of eight mental and physical domains among patients in the gastric - bypass group and two of eight domains among patients in the sleeve - gastrectomy group , as compared with the medical - therapy group . the decrease in triglyceride levels and increase in high - density lipoprotein ( hdl ) cholesterol levels in the surgical groups , as compared with intensive medical therapy , were sustained at 3 years . there were no significant differences in blood pressure among the three study groups , although there was a significant reduction in the number of medications needed to treat hyperlipidemia and hypertension in the surgical groups . there were no significant differences among the three groups in maximal carotid intima - media thickness at baseline or at 24 months . additional surgical interventions were required in four patients in the first year , including laparoscopic procedures for blood - clot evacuation , assessment of nausea and vomiting , and cholecystectomy after gastric bypass and jejunostomy for feeding access to treat gastric leak after sleeve gastrectomy . there were also no excessive weight loss or hypoalbuminiuria and no life - threatening complications or deaths in any of the groups . the 3-year outcome results of the current trial extend the earlier observations of the same trial ( 12-month follow - up ) and are consistent with the observations obtained from smaller trials ( see table 1 ) . 
  to - date , 6 randomized controlled trials compared bariatric surgery to medical therapy , 4 in patients with diabetes mellitus and 1 in patients with metabolic syndrome . the total number of patients enrolled in these trials ( including stampede ) was only 578 patients and the types of surgical techniques used varied among the trials ( gastric banding , sleeve gastretcomy , or gastric bypass . ) the current study extends those previous observations in a larger cohort of patients and over longer time follow - up . more than , 3 years after randomization , bariatric surgery as compared with intensive medical therapy alone was associated with superior and sustained glycemic control and weight reduction . analysis of secondary endpoints , including bmi , body weight , waist circumference and levels of triglycerides , and hdl cholesterol , also showed favorable results at 3 years in the surgical groups , as compared with the group receiving intensive medical therapy alone . stampede trial was a positive study demonstrating the safety and efficacy of bariatric surgery up to three years from the time of randomization among obese diabetic patients , resulting in improved glycemic control and weight reduction . the study has two main limitations , the small sample size ( although to - date it enrolled the largest number of patients among published randomized trials ) and the duration of follow - up to detect differences in incidence of diabetes complications , such as myocardial infarction , stroke or death . however , the protocol of the trial specifies further follow - up at 5 years for all patients . trials including larger numbers of patients and over longer - time periods are needed to confirm these earlier findings . moreover , bariatric surgery was performed in one highly specialized hospital by very experienced operators resulting in very low complications rates , wither these excellent surgical outcomes can be replicated by wider group of surgeons need to be monitored .
diabetes mellitus ( dm ) and obesity are associated with significant morbidity and mortality . 
 recent large - scale trials of intensive medical management for obesity and diabetes have been disappointing . 
 observational studies and small - scale trials of bariatric surgery on dm patients have shown promising results . 
 the effects of sleeve gastrectomy and gastric bypass in a larger cohort of patients with dm and obesity was tested in the stampede trial over a 3-year follow - up .