***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: Background and Purpose — Carotid artery stenosis causes up to 10 % of all ischemic strokes . Carotid endarterectomy ( CEA ) was introduced as a treatment to prevent stroke in the early 1950s . Carotid stenting ( CAS ) was introduced as a treatment to prevent stroke in 1994 . Methods — The Carotid Revascularization Endarterectomy versus Stenting Trial ( CREST ) is a r and omized trial with blinded end point adjudication . Symptomatic and asymptomatic patients were r and omized to CAS or CEA . The primary end point was the composite of any stroke , myocardial infa rct ion , or death during the periprocedural period and ipsilateral stroke thereafter , up to 4 years . Results — There was no significant difference in the rates of the primary end point between CAS and CEA ( 7.2 % versus 6.8 % ; hazard ratio , 1.11 ; 95 % CI , 0.81 to 1.51 ; P=0.51 ) . Symptomatic status and sex did not modify the treatment effect , but an interaction with age and treatment was detected ( P=0.02 ) . Outcomes were slightly better after CAS for patients aged < 70 years and better after CEA for patients aged > 70 years . The periprocedural end point did not differ for CAS and CEA , but there were differences in the components , CAS versus CEA ( stroke 4.1 % versus 2.3 % , P=0.012 ; and myocardial infa rct ion 1.1 % versus 2.3 % , P=0.032 ) . Conclusions — In CREST , CAS and CEA had similar short- and longer-term outcomes . During the periprocedural period , there was higher risk of stroke with CAS and higher risk of myocardial infa rct ion with CEA . Clinical Trial Registration — www . clinical trials.gov . Unique identifier : NCT00004732 Objective We examined how assessment s of risk of bias of primary studies are carried out and incorporated into the statistical analysis and overall findings of a systematic review . Design A cross-sectional review . Sample We assessed 200 systematic review s of r and omised trials published between January and March 2012 ; Cochrane ( n=100 ) , non-Cochrane ( Data base of Review s of Effects ) ( n=100 ) . Main outcomes Our primary outcome was a descriptive analysis of how assessment s of risk of bias are carried out , the methods used , and the extent to which such assessment s were incorporated into the statistical analysis and overall review findings . Results While Cochrane review s routinely reported the method of risk of bias assessment and presented their results either in text or table format , 20 % of non-Cochrane review s failed to report the method used and 39 % did not present the assessment results . Where it was possible to evaluate the individual results of the risk of bias assessment ( n=154 ) , 75 % ( n=116/154 ) of review s had ≥1 trial at high risk of bias ; the median proportion of trials per review at high risk of bias was 50 % ( IQR 31 % to 89 % ) . Despite this , only 56 % ( n=65/116 ) incorporated the risk of bias assessment into the interpretation of the results in the abstract and 41 % ( n=47/116 ) ( 49 % ; n=40/81 Cochrane and 20 % ; n=7/35 non-Cochrane ) incorporated the risk of bias assessment into the interpretation of the conclusions . Of the 83 % ( n=166/200 ) systematic review s which included a meta- analysis , only 11 % ( n=19/166 ) incorporated the risk of bias assessment into the statistical analysis . Conclusions Cochrane review s were more likely than non-Cochrane review s to report how risk of bias assessment s of primary studies were carried out ; however , both frequently failed to take such assessment s into account in the statistical analysis and conclusions of the systematic review Background Clinicians , providers and guideline panels use absolute effects to weigh the advantages and downsides of treatment alternatives . Relative measures have the potential to mislead readers . However , little is known about the reporting of absolute measures in systematic review s. The objectives of our study are to determine the proportion of systematic review s that report absolute measures of effect for the most important outcomes , and ascertain how they are analyzed , reported and interpreted . Methods / design We will conduct a method ological survey of systematic review s published in 2010 . We will conduct a 1:1 stratified r and om sampling of Cochrane vs. non-Cochrane systematic review s. We will calculate the proportion of systematic review s reporting at least one absolute estimate of effect for the most patient-important outcome for the comparison of interest . We will conduct multivariable logistic regression analyses with the reporting of an absolute estimate of effect as the dependent variable and pre-specified study characteristics as the independent variables . For systematic review s reporting an absolute estimate of effect , we will document the methods used for the analysis , reporting and interpretation of the absolute estimate . Discussion Our method ological survey will inform current practice s regarding reporting of absolute estimates in systematic review s. Our findings may influence recommendations on reporting , conduct and interpretation of absolute estimates . Our results are likely to be of interest to systematic review authors , funding agencies , clinicians , guideline developers and journal editors The relation between fracture risk and bone mineral density ( BMD ) is commonly expressed as a multiplicative factor which is said to represent the increase in risk for each st and ard deviation fall in BMD . This practice assumes that risk increases multiplicatively with each unit fall in bone density , which is not correct . Although odds increase multiplicatively , absolute risk , which lies between 0 and 1 , can not do so though it can be derived from odds by the term Odds/(1+Odds ) . This concept is illustrated in a prospect i ve study of 1098 women over age 69 followed for 6 years in a calcium trial in which hip BMD was measured in the second year . 304 Women ( 27.6 % ) had prevalent fractures and 198 ( 18.1 % ) incident fractures with a significant association between them ( P 0.005 ) . Age-adjusted hip BMD and T-score were significantly lower in those with prevalent fractures than in those without ( P 0.003 ) and significantly lower in those with incident fractures than in those without ( P 0.001 ) . When the data were analysed by univariate logistic regression , the fracture odds at zero T-score were 0.130 and the rise in odds for each unit fall in hip T-score was 1.55 . When these odds were converted to risks , there was a progressive divergence between odds and risk at T-scores below zero . Multiple logistic regression yielded significant odds ratios of 1.47 for each 5-year increase in age , 1.47 for prevalent fracture and 1.49 for each unit fall in hip T-score . Calcium therapy was not significant . Poisson regression , logistic regression and Cox 's proportional hazards yielded very similar outcomes when converted into absolute risks . A nomogram was constructed to enable clinicians to estimate the approximate 6-year fracture risk from hip T-score , age and prevalent fracture which can probably be applied ( with appropriate correction ) to men as well as to women . We conclude that multiplicative factors can be applied to odds but not to risk and that multipliers of risk tend to overstate the effect of continuous variables , such as age and T-score , particularly towards the end of their ranges OBJECTIVE To compare clinicians ' ratings of therapeutic effectiveness when different trial end points were presented as percent reductions in relative compared with absolute risk and as numbers of patients treated to avoid one adverse outcome . DESIGN Survey , with r and om allocation of two question naires . SETTING Toronto teaching hospitals . RESPONDENTS Convenience sample of 100 faculty and housestaff in internal medicine and family medicine . INTERVENTION One question naire presented results for three end points of the Helsinki Heart Study as separate drug trials using only absolute differences in events ; the other showed the same end points as relative differences . Both question naires included a fourth " trial , " showing person-years of treatment needed to prevent one myocardial infa rct ion . MAIN OUTCOME MEASURE The " trials " were each rated on an 11-point scale , from treatment " harmful " to " very effective . " RESULTS Respondents ' ratings of effectiveness varied with the end point . Controlling for end point , ratings of effectiveness by the 50 participants receiving absolute event data were lower than those by 50 participants responding to relative risk reductions ( P < 0.001 ) ; however , no end-point difference was more than 0.6 scale points . For a " trial " reporting that 77 persons were treated for 5 years to prevent one myocardial infa rct ion , mean ratings were 2.3 or 1.8 scale points lower , respectively ( both P < 0.001 ) , than when the same data were shown as relative or absolute risk reductions . CONCLUSIONS Clinicians ' views of drug therapies are affected by the common use of relative risk reductions in both trial reports and advertisements , by end-point emphasis , and , above all , by underuse of summary measures that relate treatment burden to therapeutic yields in a clinical ly relevant manner Objective To examine the accessibility of absolute risk in articles reporting ratio measures in leading medical journals . Design Structured review of abstract s presenting ratio measures . Setting Articles published between 1 June 2003 and 1 May 2004 in Annals of Internal Medicine , BMJ , Journal of the American Medical Association , Journal of the National Cancer Institute , Lancet , and New Engl and Journal of Medicine . Participants 222 articles based on study design s in which absolute risks were directly calculable ( 61 r and omised trials , 161 cohort studies ) . Main outcome measure Accessibility of the absolute risks underlying the first ratio measure in the abstract . Results 68 % of articles ( 150/222 ) failed to report the underlying absolute risks for the first ratio measure in the abstract ( range 55−81 % across the journals ) . Among these articles , about half did report the underlying absolute risks elsewhere in the article ( text , table , or figure ) but half did not report them anywhere . Absolute risks were more likely to be reported in the abstract for r and omised trials compared with cohort studies ( 62 % v 21 % ; relative risk 3.0 , 95 % confidence interval 2.1 to 4.2 ) and for studies reporting crude compared with adjusted ratio measures ( 62 % v 21 % ; relative risk 3.0 , 2.1 to 4.3 ) . Conclusion Absolute risks are often not easily accessible in articles reporting ratio measures and sometimes are missing altogether — this lack of accessibility can easily exaggerate readers ' perceptions of benefit or harm BACKGROUND Uncertainty and risk are central issues in relation to health and health care services . Healthy individuals do not necessarily fall ill , despite the presence of risk factors . It has been documented that doctors , health service administrators and patients are more inclined to choose interventions against risk factors when information about the effects is presented in terms of relative risk reductions rather than absolute risk reductions . OBJECTIVES The objective of the study was to gain better insight into how GPs perceive risk of disease , and how this perception is influenced by the way the risk is presented , e.g. whether changes in risk are presented in absolute or relative terms . METHODS Question naires with clinical episodes were sent to 1500 Danish GPs . The GPs were r and omized into four groups of 375 , who all received the same case story with information about risk reduction achieved through medical treatment phrased in terms of either relative risk reduction , absolute risk reduction , number needed to treat or all of the aforementioned terms of risk reduction . The GPs were asked whether they would recommend medical treatment as primary prevention , knowing the case story and expected risk reduction . RESULTS The GPs ' attitude towards recommending medical treatment was dependent on the phrasing of risk reductions . Seventy-two per cent of doctors who received all information on risk reductions would definitely or probably recommend medication , while 91 % would recommend medication if information only about relative risk reduction was given , and 63 % would recommend medication if information was given in terms of absolute risk reduction or number needed to treat . CONCLUSION In order to advise patients in a rational way , in addition to knowledge of the patients ' preferences , doctors need to take into account all available measures of risk reductions 
    Output:
    
Most SRs do not report absolute effects .