***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: OBJECTIVES : It has been suggested that the variation in the prevalence of irritable bowel syndrome ( IBS ) may be due to the application of different diagnostic criteria . New criteria for IBS have been proposed ( Rome II ) . It is unknown whether persons meeting different criteria for IBS have similar psychological and symptom features . The aim of this study was to measure the prevalence of IBS according to Manning and Rome definitions of IBS and to evaluate the clinical and psychological differences between diagnostic categories . METHODS : A total of 4500 r and omly selected subjects , with equal numbers of male and female subjects aged ≥18 yr and representative of the Australian population , took part in this study . Subjects were mailed a question naire ( response rate , 72 % ) . Characteristics measured were gastrointestinal symptoms over the past 12 months , neuroticism and extroversion ( Eysenck Personality Question naire ) , anxiety and depression ( Delusions-Symptoms-States Inventory ) , mental and physical functioning ( SF-12 ) , and somatic distress ( Sphere ) . RESULTS : The prevalence for IBS according to Manning , Rome I , and Rome II was 4.4 % ( 95 % confidence interval [ CI ] = 3.5–5.1 % ) , 6.9 % ( CI 6.0–7.8 % ) , and 13.6 % ( CI 12.3–14.8 % ) , respectively . Only 12 persons with Rome I did not also meet Rome II criteria ; 196 persons with Manning criteria did not meet Rome II cut-offs . Having IBS regardless of which criteria were used was significantly associated with psychological morbidity , but psychological factors were not important in discriminating between diagnostic categories . However , pain and bowel habit severity independently discriminated between diagnostic groups . CONCLUSIONS : IBS is a relatively common disorder in the community . The new Rome II criteria may be unnecessarily restrictive in practice Over a 3‐year period , all patients referred for barium enema examination  had a double‐contrast barium enema and flexible sigmoidoscopy performed on the same day . A total of 462 joint examinations were performed . Abnormalities were found in 193 patients by the use of barium enema , 164 patients by using sigmoidoscopy and 294 by the use of both methods of investigation .  Sigmoidoscopy was superior to barium enema in the detection of polyps and inflammatory bowel disease but barium enema was more sensitive for diverticular disease . The presenting symptoms had no predictive value in distinguishing carcinoma , polyps and diverticular disease . Diverticular disease did not reduce the sensitivity of barium enema examination to polyps in the sigmoid colon . Fibreoptic sigmoidoscopy immediately before barium enema was well tolerated by patients . The investigations were complementary in the diagnosis of colonic polyps , inflammatory bowel disease and diverticular disease In a prospect i ve study involving 833 consecutive outpatient and open-access colonoscopies , attempts were made to characterize the benefit of colonoscopy in terms of both predicted and unpredicted findings and therapeutic procedures . The endoscopist therefore predicted the endoscopic findings before the endoscopy . The results were compared for the different indications for colonoscopy . The overall agreement between the predictions and the colonoscopic findings was 61 % . Clinical ly significant abnormalities were found in about half the examinations . The most frequent abnormal findings were benign polyps ( 24 % ) , inflammatory bowel disease ( 17 % ) , and malignancy ( 5 % ) . In about half the patients with a malignancy the indication for colonoscopy was rectal bleeding , and half of the malignancies were not predicted . The greatest benefit of colonoscopy  was found in patients referred because of overt rectal bleeding or occult faecal blood , and abnormal barium enema or endoscopy findings . The importance of complete colonoscopy in connection with operation for colorectal carcinoma is emphasized Colonoscopy is an integral part of the clinician armamentarium in the diagnosis of colorectal cancer and its precursor , the adenoma . Polypoid lesions when identified can be excised at colonoscopy and in turn reduce the risk of colorectal cancer . We prospect ively evaluated the yield of colorectal cancer and adenomatous polyps  by indication for colonoscopy  over a one-year period . A total of 375 colonoscopies were carried out . The more common indications of colonoscopy were rectal bleeding , abdominal pain , surveillance of colorectal cancer and altered bowel habit . The highest yield for cancer was for rectal bleeding with 12.5 % while surveillance of patients with a history of polyps yielded the highest percentage of new polyps . We conclude that rectal bleeding as an indication for colonoscopy yielded the highest number of cancers OBJECTIVES To assess the clinical yield of colonoscoping in patients who present with rectal bleeding , persistent abdominal pain , or change in bowel habits in the absence of bleeding . DESIGN A prospect i ve study of  colonoscopy patients . SETTING Three colonoscopy practice s in New York City between April 1986 and November 1989 . PATIENTS Eight hundred sixty-one patients with rectal bleeding , 113 patients with abdominal pain , 154 with change in bowel habits , and 44 patients with both abdominal pain and bowel change . MAIN RESULTS Of 861 patients with rectal bleeding , 293 ( 33.6 % ) had colonic neoplasia ( 8.6 % cancer and 25 % adenomatous polyps ) . In patients who had colonoscopy because of abdominal pain ( n = 113 ) , change in bowel habits ( n = 154 ) , or both abdominal pain and bowel change ( n = 44 ) , respectively 25 ( 22.1 % ) , 42 ( 27.3 % ) , and 10 ( 22.7 % ) had colonic neoplasms . If one looks at significant neoplasia ( cancer or adenomas > 1 cm ) , then the findings in rectal bleeders were 14.5 % , whereas the abdominal pain , change in bowel habits , and both groups had 7.1 % , 7.1 % , and 13.6 % , respectively . Patients with rectal bleeding were more likely to have multiple adenomas than those with nonbleeding symptoms ( p < 0.05 ) . CONCLUSIONS Patients with persistent nonbleeding GI symptoms , including abdominal pain and change in bowel habits  , have almost as high a yield of colorectal neoplasia as those with rectal bleeding BACKGROUND AND STUDY AIMS Appropriateness of use of colonoscopy is an important issue in health care in the quest to improve quality of care while at the same time containing costs . This prospect i ve study examined whether detailed and explicit appropriateness criteria significantly improve the diagnostic yield of colonoscopy .  PATIENTS AND METHODS Consecutive patients referred for diagnostic colonoscopy at five centers ( one university hospital and its outpatient department , two district hospitals , and two gastroenterology practice s ) were prospect ively studied over a 17-month period . The appropriateness of the indications for these colonoscopies was assessed using explicit Swiss criteria developed by the R and Corporation/University of California at Los Angeles ( R AND /UCLA ) panel method , and the relationship between appropriateness of use and the presence of clinical ly relevant endoscopic lesions was analysed . RESULTS 1188 patients were included in the study . Indications for 1144 ( 96.3 % ) of the colonoscopies could be evaluated using explicit criteria ; 64.1 % of the colonoscopies were judged appropriate , 13.3 % uncertain and 22.6 % inappropriate . Significant endoscopic lesions were found in 23.8 % of the colonoscopies . Colonoscopies judged appropriate or uncertain yielded significantly more relevant lesions than did those judged to be inappropriate ( 25.6 % vs. 17.4 % ; P = 0.007 ) . Of 51 colon cancers , all but one were found in colonoscopies judged to be appropriate or uncertain . In a multivariate analysis , the diagnostic yield of colonoscopy  was significantly influenced by appropriateness , patient gender and treatment setting . CONCLUSIONS The use of detailed and explicit appropriateness criteria for colonoscopy significantly enhances the identification of relevant lesions and in particular of colon cancer . The use of such criteria could therefore improve patient selection for colonoscopy and thus contribute to efforts aim ed at enhancing the quality and efficiency of care Objective : Little data on  rectal bleeding  in the U.S. population are available . We therefore sought to assess the prevalence of different types of rectal bleeding , their association with potential risk factors including other colonic symptoms , and predictors of health care seeking in a U.S. community . Methods : We used a crossectional survey by mail , applying a previously vali date d self-report symptom question naire . Our population comprised an age- and gender-stratified r and om sample of Olmsted County , Minnesota residents aged 20–64 yr . Results : In total , 1643 responded ( 77 % ) .  Rectal bleeding was reported by 235 subjects ( age- and gender-adjusted prevalence , 15.5 per 100 ; 95 % confidence interval [ CI ] , 13.6–17.4 ) ; 218 found blood on wiping , 74 noted blood coating the stools , and 46 reported dark blood mixed in the stools . The prevalence of rectal bleeding was significantly higher in younger persons ( 18.9 % , 20–40 yr vs 11.3 % > 40 yr ; p < 0.001 ) . By stepwise logistic regression analysis , constipation ( odds ratio [ OR ] = 3.03 ; 95 % CI , 2.09–4.41 ) and diarrhea ( OR = 1.90 ; 95 % CI , 1.25–2.84 ) were independent predictors of rectal bleeding . Among those with rectal bleeding , 13.9 % ( 95 % CI , 9.6–19.1 % ) had visited a physician for bowel problems in the prior yr ; only a history of abdominal surgery was an independent predictor of physician visits but this explained just 15.9 % of the deviance . Conclusions : In otherwise healthy young and middle-aged persons , approximately one in seven have a history of rectal bleeding and this is more frequent in younger people ; only a minority seek health care and this is not related to symptom status BACKGROUND Open-access endoscopy allows physicians to directly schedule endoscopic procedures for their patients without prior consultation . Evaluation of both appropriateness and diagnostic yield of endoscopic procedures is critical when assessing the costs and benefits of endoscopy in an open-access setting . The aim of this study was to assess the appropriate use of colonoscopy in an open-access system and to establish the yield of diagnostic information relevant to patient care . METHODS Overall , 1123 consecutive patients referred for open-access colonoscopy were prospect ively enrolled in the study . The American Society for Gastrointestinal Endoscopy ( ASGE ) guidelines were used to assess the relationship between the appropriate use of colonoscopy and the presence of relevant endoscopic findings . RESULTS The rate of colonoscopies " generally not indicated " according to ASGE guidelines was 29 % ( 39 % for primary care physicians and 23 % for specialists ; p < 0.0001 ) . A relevant endoscopic finding was detected in 338 examinations ( 35 % ) . The diagnostic yield was significantly higher for " generally indicated " colonoscopies ( 43 % ) compared with " generally not indicated " procedures ( 16 % ) ( p < 0.001 ) . CONCLUSIONS Although the rate of inappropriate use of colonoscopy was high , open-access colonoscopy was effective in detecting neoplastic lesions . Because most of these were detected during examinations performed for appropriate indications , the appropriateness of the indication emerges as crucial to the cost-effectiveness of an open-access system 
    Output:
    
Most alarm features had poor sensitivity and specificity for the diagnosis of colorectal carcinoma , whilst statistical models performed better in terms of sensitivity .