***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 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: OBJECTIVE To assess whether a pragmatic policy of perioperative beta-blockade , with metoprolol , reduced the 30-day cardiovascular morbidity and mortality and reduced the length of hospital stay in average patients undergoing infrarenal vascular surgery . METHODS This was a double-blind r and omized placebo-controlled trial that occurred in vascular surgical units in four UK hospitals . Participants were 103 patients without previous myocardial infa rct ion who had infrarenal vascular surgery between July 2001 and March 2004 . Interventions were oral metoprolol ( 50 mg twice daily , supplemented by intravenous doses when necessary ) or placebo from admission until 7 days after surgery . Holter monitors were kept in place for 72 hours after surgery . RESULTS Eighty men and 23 women ( median age , 73 years ) were r and omized , 55 to  metoprolol  and 48 to placebo , and 97 ( 94 % ) underwent surgery during the trial . The most common operations were aortic aneurysm repair ( 38 % ) and distal bypass ( 29 % ) . Intraoperative inotropic support was required in 64 % and 92 % of patients in the placebo and metoprolol groups , respectively . Within 30 days , cardiovascular events occurred in 32 patients , including myocardial infa rct ion ( 8 % ) , unstable angina ( 9 % ) , ventricular tachycardia ( 19 % ) , and stroke ( 1 % ) . Four ( 4 % ) deaths were reported . Cardiovascular events occurred in 15 ( 34 % ) and 17 ( 32 % ) patients in the placebo and metoprolol groups , respectively ( unadjusted relative risk , 0.94 ; 95 % confidence interval , 0.53 - 1.66 ; adjusted [ for age , sex , statin use , and aortic cross-clamping ] relative risk , 0.87 ; 95 % confidence interval , 0.48 - 1.55 ) . Time from operation to discharge was reduced from a median of 12 days ( 95 % confidence interval , 9 - 19 days ) in the placebo group to 10 days ( 95 % confidence interval , 8 - 12 days ) in the metoprolol group ( adjusted hazard ratio , 1.71 ; 95 % confidence interval , 1.09 - 2.66 ; P < .02 ) . CONCLUSIONS Myocardial ischemia was evident in a high proportion ( one third ) of the patients after surgery . A pragmatic regimen of perioperative beta-blockade with metoprolol did not seem to reduce 30-day cardiovascular events , but it did decrease the time from surgery to discharge BACKGROUND Type 2 diabetes mellitus is increasingly common , primarily because of increases in the prevalence of a sedentary lifestyle and obesity . Whether type 2 diabetes can be prevented by interventions that affect the lifestyles of subjects at high risk for the disease is not known . METHODS We r and omly assigned 522 middle-aged , overweight subjects ( 172 men and 350 women ; mean age , 55 years ; mean body-mass index [ weight in kilograms divided by the square of the height in meters ] , 31 ) with impaired glucose tolerance to either the intervention group or the control group . Each subject in the intervention group received individualized counseling aim ed at reducing weight , total intake of fat , and intake of saturated fat and increasing intake of fiber and physical activity . An oral glucose-tolerance test was performed annually ; the diagnosis of diabetes was confirmed by a second test . The mean duration of follow-up was 3.2 years . RESULTS The mean ( + /-SD ) amount of weight lost between base line and the end of year 1 was 4.2+/-5.1 kg in the intervention group and 0.8+/-3.7 kg in the control group ; the net loss by the end of year 2 was 3.5+/-5.5 kg in the intervention group and 0.8+/-4.4 kg in the control group ( P<0.001 for both comparisons between the groups ) . The cumulative incidence of diabetes after four years was 11 percent ( 95 percent confidence interval , 6 to 15 percent ) in the intervention group and 23 percent ( 95 percent confidence interval , 17 to 29 percent ) in the control group . During the trial , the risk of diabetes was reduced by 58 percent ( P<0.001 ) in the intervention group . The reduction in the incidence of diabetes was directly associated with changes in lifestyle . CONCLUSIONS Type 2 diabetes can be prevented by changes in the lifestyles of high-risk subjects Abstract Objectives To evaluate the long term effects of perioperative β blockade on mortality and cardiac morbidity in patients with diabetes undergoing major non-cardiac surgery . Design R and omised placebo controlled and blinded multicentre trial . Analyses were by intention to treat . Setting University anaesthesia and surgical centres and one coordinating centre . Participants 921 patients aged > 39 scheduled for major non-cardiac surgery . Interventions 100 mg metoprolol controlled and extended release or placebo administered from the day before surgery to a maximum of eight perioperative days . Main outcome measures The composite primary outcome measure was time to all cause mortality , acute myocardial infa rct ion , unstable angina , or congestive heart failure . Secondary outcome measures were time to all cause mortality , cardiac mortality , and non-fatal cardiac morbidity . Results Mean duration of intervention was 4.6 days in the metoprolol group and 4.9 days in the placebo group . Metoprolol significantly reduced the mean heart rate by 11 % ( 95 % confidence interval 9 % to 13 % ) and mean blood pressure by 3 % ( 1 % to 5 % ) . The primary outcome occurred in 99 of 462 patients in the metoprolol group ( 21 % ) and 93 of 459 patients in the placebo group ( 20 % ) ( hazard ratio 1.06 , 0.80 to 1.41 ) during a median follow-up of 18 months ( range 6 - 30 ) . All cause mortality was 16 % ( 74/462 ) in the metoprolol group and 16 % ( 72/459 ) in the placebo group ( 1.03 , 0.74 to 1.42 ) . The difference in risk for the proportion of patients with serious adverse events was 2.4 % ( − 0.8 % to 5.6 % ) . Conclusions Perioperative metoprolol did not significantly affect mortality and cardiac morbidity in these patients with diabetes . Confidence intervals , however , were wide , and the issue needs re assessment . Trial registration Current Controlled Trials IS RCT N58485613 [ controlled-trials.com OBJECTIVE Individuals with impaired glucose tolerance ( IGT ) have a high risk of developing NIDDM . The purpose of this study was to determine whether diet and exercise interventions in those with IGT may delay the development of NIDDM , i.e. , reduce the incidence of NIDDM , and thereby reduce the overall incidence of diabetic complications , such as cardiovascular , renal , and retinal disease , and the excess mortality attributable to these complications . RESEARCH DESIGN AND METHODS In 1986 , 110,660 men and women from 33 health care clinics in the city of Da Qing , China , were screened for IGT and NIDDM . Of these individuals , 577 were classified ( using World Health Organization criteria ) as having IGT . Subjects were r and omized by clinic into a clinical trial , either to a control group or to one of three active treatment groups : diet only , exercise only , or diet plus exercise . Follow-up evaluation examinations were conducted at 2-year intervals over a 6-year period to identify subjects who developed NIDDM . Cox 's proportional hazard analysis was used to determine if the incidence of NIDDM varied by treatment assignment . RESULTS The cumulative incidence of diabetes at 6 years was 67.7 % ( 95 % CI , 59.8–75.2 ) in the control group compared with 43.8 % ( 95 % CI , 35.5–52.3 ) in the diet group , 41.1 % ( 95 % CI , 33.4–49.4 ) in the exercise group , and 46.0 % ( 95 % CI , 37.3–54.7 ) in the diet-plus-exercise group ( P < 0.05 ) . When analyzed by clinic , each of the active intervention groups differed significantly from the control clinics ( P < 0.05 ) . The relative decrease in rate of development of diabetes in the active treatment groups was similar when subjects were stratified as lean or overweight ( BMI < or ≥ 25 kg/m2 ) . In a proportional hazards analysis adjusted for differences in baseline BMI and fasting glucose , the diet , exercise , and diet-plus-exercise interventions were associated with 31 % ( P < 0.03 ) , 46 % ( P < 0.0005 ) , and 42 % ( P < 0.005 ) reductions in risk of developing diabetes , respectively . CONCLUSIONS Diet and /or exercise interventions led to a significant decrease in the incidence of diabetes over a 6-year period among those with IGT The preliminary results of the twelfth Medical Research Council acute myeloid leukemia trial show no evidence of a survival advantage for five courses of therapy compared to four courses in a r and omized comparison involving 1078 patients ( hazard ratio 1.09 , 95 % confidence interval [ CI ] 0.87 - 1.37 , p=0.4 ) . However , the data presented to the independent data monitoring and ethics committee ( DMEC ) at both its review s in 1998 suggested large benefits for the additional course with hazard ratios of 0.47 and 0.55 ( 95 % CIs 0.29 - 0.77 and 0.38 - 0.80 , p=0.003 and p=0.002 , respectively ) . Despite these highly significant findings , the DMEC did not recommend closure of the r and omization , a decision vindicated by the subsequent reversion to a null result . The main reason for not closing the r and omization was that the treatment effects observed in 1998 ( 53 % and 45 % reductions in the odds of death ) were considered too large to be clinical ly plausible , despite the p-values associated with them . Investigations have not identified any clinical explanations , such as different types of patients in the early and later parts of the trial , to explain the loss of benefit as the trial progressed . Thus , the most likely current explanation for the large benefit observed early on is the play of chance . Lessons to be learned from this example are that : fixed stopping rules based on some predetermined p-value should not be used and the decision to close a r and omization or not should take account of other factors such as the medical plausibility of the magnitude of the treatment effect ; chance effects do occur and happen more frequently than many clinicians realize ; it is important that DMEC members are experienced in the interpretation of clinical trial evidence and aware of the dangers of early stopping without wholly convincing evidence BACKGROUND Type 2 diabetes affects approximately 8 percent of adults in the United States . Some risk factors -- elevated plasma glucose concentrations in the fasting state and after an oral glucose load , overweight , and a sedentary lifestyle -- are potentially reversible . We hypothesized that modifying these factors with a lifestyle-intervention program or the administration of metformin would prevent or delay the development of diabetes . METHODS We r and omly assigned 3234 nondiabetic persons with elevated fasting and post-load plasma glucose concentrations to placebo , metformin ( 850 mg twice daily ) , or a lifestyle-modification program  with the goals of at least a 7 percent weight loss and at least 150 minutes of physical activity per week . The mean age of the participants was 51 years , and the mean body-mass index ( the weight in kilograms divided by the square of the height in meters ) was 34.0 ; 68 percent were women , and 45 percent were members of minority groups . RESULTS The average follow-up was 2.8 years . The incidence of diabetes was 11.0 , 7.8 , and 4.8 cases per 100 person-years in the placebo , metformin , and lifestyle groups , respectively . The lifestyle intervention reduced the incidence by 58 percent ( 95 percent confidence interval , 48 to 66 percent ) and metformin by 31 percent ( 95 percent confidence interval , 17 to 43 percent ) , as compared with placebo ; the lifestyle intervention was significantly more effective than metformin . To prevent one case of diabetes during a period of three years , 6.9 persons would have to participate in the lifestyle-intervention program , and 13.9 would have to receive metformin . CONCLUSIONS Lifestyle changes and treatment with metformin both reduced the incidence of diabetes in persons at high risk . The lifestyle intervention was more effective than metformin A r and omized , double-blind study to determine the effect of intramuscular vitamin E on mortality and intracranial hemorrhage ( ICH )  was performed . One hundred forty-nine neonates with birth weights less than or equal to 1000 g 
    Output:
    
These results , which are consistent with predictions from statistical theory ( 3 ) , suggest that stopping trials early for apparent benefit will systematic ally overestimate treatment effects .
Had the investigators terminated the trial in accordance with their stopping rule , subsequent patients with leukemia may have experienced the toxicity of an additional course of chemotherapy without benefit .