***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    Input: Eighty-seven morbidly obese patients were prospect ively r and omized to two operations : gastric bypass was performed on 42 and gastric partition on 45 . Gastric bypass proved to be more effective ; gastric bypass patients lost 15 % more of their original weight at 12 months and 21 % more at 18 months . There were no failures in the gastric bypass group ; 28 of the 45 operations failed in the gastric partition group . An additional 60 patients underwent gastric bypass since the completion of the study . In the total series of 147 patients who underwent gastric bypass or gastric partition  , there was no mortality , and the surgical complication rate was 12 % . Because the gastric pouches and the anastomoses were similar in the two operations , the superiority of the gastric bypass may well be due to a heretofore unexplained effect of distal gastric and duodenal exclusion The present status of 38 patients comprising a clinical trial of jejunoileal and gastric bypass for the treatment of morbid obesity , begun four years ago at North Carolina Memorial Hospital , is reported . Weight loss was greater in patients treated by jejunoileal bypass  than those treated by gastric bypass .  The poorer weight loss noted in the  gastric bypass patients is associated with an excessively large proximal gastric pouch , which had characterized the 19  gastric bypass operations done prior to May 1977 . The weight loss achieved with the current version of the gastric bypass , a smaller proximal gastric pouch , is comparable to that achieved with jejunoileal bypass . The objective and subjective sequelae and complications of jejunoileal bypass are more common and more serious than those of gastric bypass . Gastric bypass is the better operation for the treatment of morbid obesity For 2 years , 12 Danish hospitals have conducted a r and omized clinical trial to evaluate the hazards and benefits of jejunoileal bypass operations for severe obesity . At present ( January , 1976 ) , there are 92 operated and 46 unoperated patients . There has been no mortality in the operated group . One control patient has died . Weight loss is significantly better in the operated group , but not always satisfactory . The well-known postoperative complications have not been deterring in frequency or seriousness . On the whole , but not invariably , the operation has been followed by an improvement in psychosocial status Background : The feasibility of laparoscopic Roux-en-Y gastric bypass ( Lap-RYGBP ) for morbid obesity is well documented . In a prospect i ve r and omized trial , we compared laparoscopic and open surgery . Methods : 51 patients ( 48 females , mean ( ± SD ) age 36 ± 9 years and BMI 42 ± 4 kg/m2 ) were r and omly allocated to either laparoscopy ( n=30 ) or open surgery ( n=21 ) . All patients were followed for a minimum of 1 year . Results : In the laparoscopy group , 7 patients ( 23 % ) were converted to open surgery  due to various procedural difficulties . In an analysis , with the converted patients excluded , the morphine doses used postoperatively were significantly ( p < 0.005 ) lower in the laparoscopic group compared to the open group . Likewise , postoperative hospital stay was shorter ( 4 vs 6 days , p<0.025 ) . Six patients in the laparoscopy group had to be re-operated due to Roux-limb obstruction in the mesocolic tunnel within 5 weeks . The weight loss expressed in decrease in mean BMI units after year was 14 and 13 after 1 ± 3 ± 3 laparoscopy and open surgery , respectively ( not significant ) . Conclusions : Both laparoscopic and open RYGBP are effective and well received surgical procedures in morbid obesity . Reduced postoperative pain , shorter hospital stay and shorter sick-leave are obvious benefits of laparoscopy but conversions and /or reoperations in 1/4 of the patients indicate that Lap-RYGBP at present must be considered an investigational procedure OBJECTIVE To examine the effect of a large , long st and ing and intentional weight reduction on the incidence of diabetes , hypertension and lipid disturbances in severely obese individuals as compared to weight-stable obese controls . RESEARCH METHODS AND PROCEDURES The ongoing prospect i ve SOS ( Swedish Obese Subjects ) intervention consists of a surgically treated group and a matched control group obtaining conventional obesity treatment . This report is based on 845 surgically treated patients and 845 controls ( BMI 41.0+/-4.6 kg/m2 ( mean+/-st and ard deviation [ S ] ) ) followed for 2 years . RESULTS Surgically treated patients lost 28+/-15 kg and controls 0.5+/-8.9 kg ( p<0.0001 ) . Two-year incidence of hypertension , diabetes , hyperinsulinemia , and lipid disturbances was compared in the two treatment groups . Adjusted odds ratios ( 95 % CI ) for the surgically treated group versus controls were 0.38 ( 0.22 , 0.65 ) for hypertension , 0.02 ( 0.00 , 0.16 ) for diabetes , 0.10 ( 0.03 , 0.28 ) for hyperinsulinemia , 0 . 10 ( 0.04 , 0.25 ) for hypertriglyceridemia , 0.28 ( 0.16 , 0.49 ) for low HDL-cholesterol and 1.24 ( 0.84 , 1.8 ) for hypercholesterolemia . Compared to controls , the 2-year recovery rates from hypertension , diabetes , hypo-HDL , and hypertriglyceridemia were significantly higher in the surgically treated group . DISCUSSION Intentional weight loss in the obese causes a marked reduction in the 2-year incidence of hypertension , diabetes and some lipid disturbances . The results suggest that severe obesity can and should be treated 57 morbidly obese patients were r and omized and operated upon with gastric bypass ( GBY ) or gastroplasty ( GPL ) .  The patients were followed for three years . GBY had a slightly higher early complication rate but a significantly ( p less than 0.001 ) greater weight loss .  GBY lost 42.3 + /- 10.9 kg after one year and 38.4 + /- 12.3 kg after three years compared to 29.9 + /- 10.0 kg one year and 24.7 + /- 13.1 kg three years after GPL .  No GBY but 10 GPL patients were reoperated upon due to failure to lose or to maintain lost weight . An endoscopic method was developed for postoperative measurement of stoma diameter . Use of this method showed no significant difference in stoma diameter between GBY and GPL . A correlation between weight loss and stoma diameter was found one year after GPL but not after GBY . Also a correlation between peroperative pouch volume and weight loss was seen after GPL but not after GBY . The two methods differed in emptying rate of a semi-solid test meal from the upper gastric pouch . For both methods the energy intake was highly reduced postoperatively , but significantly more after GBY . For a number of nutrients the intake was below minimum recommended levels . Fat cell weight was reduced postoperatively , most pronounced for the abdominal regions and least for the femoral-gluteal regions . The reduction was also significantly more pronounced after GBY than after GPL . Calculated fat cell number was significantly reduced after both methods . It is concluded that the effect on body weight of GPL and GBY can not be explained by the same mode of action . In GPL mechanical fractures such as pouch volume and stoma size are of great importance , which is in accordance with earlier theories . In contrast to this , the results of GBY can not be satisfactorily explained by such mechanical factors and additional mechanisms , probably of neuro-endocrinologic origin , must be sought for A prospect i ve r and omized clinical trial was undertaken to compare the effects of  gastric bypass with Roux-en-Y gastro-jejunostomy and a gastric partitioning procedure .  Operative groups were comparable , with regard to preoperative weight , age , sex , historic findings and operative complications . Postoperative weight loss was followed for one year . Patients receiving the gastric partitioning procedure  showed significantly poorer weight loss as early as three months postoperatively than did those receiving gastric bypass .  This poorer performance persisted throughout the study period Fifty-one morbidly obese women were r and omized to surgical treatment with gastric bypass ( GBY ) or gastroplasty ( GPL ) .  Their dietary intake was assessed preoperatively and 12 months postoperatively by two methods : diet history and 4-day weighted intake . Their protein intake was also checked against urinary nitrogen losses . There was a good correspondence between the results of the two dietary methods and also between estimated protein intake and urinary loss . This makes the results reliable . After 1 year the  GBY patients demonstrated a mean weight loss of 41.6 + /- 10.8 kg ( P less than 0.001 versus GPL ) and a mean energy intake preoperatively of about 2400 kcal/day and postoperatively of 1050 kcal/day ( P less than 0.05 versus GPL ) . The GPL  patients lost 28.9 + /- 9.6 kg as a mean and had a preoperative intake of about 2500 kcal/day and a postoperative intake of about 1300 kcal/day . There were only minor changes in the quality of the food from the preoperative to the postoperative situation . Postoperatively the daily intake of several nutrients was below minimum values of recommended or required intake The beneficial effects of weight loss in the obese have been widely accepted . Still , there is a lack of controlled studies displaying large maintained weight losses over long periods ( > 4 years ) . We wanted to examine the results of long-st and ing intentional weight loss on the development of diabetes and hypertension in severely obese individuals over an 8-year period . In the ongoing prospect i ve Swedish Obese Subjects ( SOS ) study , 346 patients awaiting gastric surgery were matched with 346 obese control subjects on 18 variables by a computerized matching program . The controls were drawn from a registry consisting of 1508 obese potential controls examined at primary health care centers in Sweden . Of the 692 selected patients ( body mass index 41.2+/-4.7 kg/m(2 ) [ mean+/-SD ] ) , 483 ( 70 % ) were followed for 8 years . No significant weight changes occurred in the obese control group over 8 years . Gastric surgery result ed in a maximum weight loss of -31.1+/-13.6 kg after 1 year . After 8 years , the maintained weight loss was still 20.1+/-15.7 kg ( 16.3+/-12.3 % ) . Whereas this weight reduction had a dramatic effect on the 8-year incidence of diabetes ( odds ratio 0.16 , 95 % CI 0.07 to 0.36 ) , it had no effect on the 8-year incidence of hypertension ( odds ratio 1.01 , 95 % CI 0.61 to 1.67 ) . A differentiated risk factor response was identified : a maintained weight reduction of 16 % strongly counteracted the development of diabetes over 8 years but showed no long-term effect on the incidence of hypertension Vertical b and ed gastroplasty ( VBGP ) was compared with Roux-en-Y gastric bypass ( RYGBP ) in a r and omized prospect i ve trial that included preoperative dietary separation of " sweets eaters " versus " non-sweets eaters . " R and omization was stopped at 9 months after 20 patients had undergone each procedure because a greater weight loss ( p less than 0.05 ) was noted after RYGBP than VBGP . This difference became more significant ( p less than 0.001 ) at each 3-month interval through 3 years , when patients who had VBGPs had lost 37 + /- 20 % of excess weight compared with 64 + /- 19 % for patients who had RYGBPs . The members of the groups were comparable with regard to age , sex , eating habits , morbidity rates before surgery , ideal body weight , and weight before surgery . Although there was no significant difference between the loss of excess weight in " sweets eaters " ( 69 + /- 17 % ) or " non-sweets eaters " ( 67 + /- 17 % ) after RYGBP at 1 year , " sweets eaters " who had VBGPs lost significantly less excess weight ( 36 + /- 13 % ) than did " non-sweets eaters " who had VBGPs ( 57 + /- 18 % ) , p less than 0.02 , or " sweets eaters " who had RYGBPs , p less than 0.0001 . No significant differences were noted for electrolytes , renal or liver function tests , and most vitamins between patients who had VBGPs and RYGBPs ; however , patients who had RYGBPs had lower ( p less than 0.05 ) serum vitamin B12 levels ( 286 + /- 149 pg/dl ) than did patients who had VBGPs ( 461 + /- 226 pg/dl ) at 2 years . By 3 years , the vitamin B12 levels were equal in members of the two groups . Five patients who had RYGBPs required endoscopic stomal dilatation for stomal stenosis and one had a marginal ulcer develop , which responded to cimet 
    Output:
    
Surgery result ed in a significantly greater loss of weight ( 23–37 kg more weight ) than nonsurgical treatment , which was maintained to 8 years and led to improvements in quality of life and comorbidities .
: Surgery for morbid obesity appears to be clinical ly and cost effective .
Because of the nature of the evidence , particularly the uncertainty in the clinical and economic evaluations , it is difficult to distinguish between the different surgical procedures