human
***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: Eighty-nine patients who had been treated by ileal resection for Crohn 's disease between 1979 and 1984 were included in a prospect i ve cohort follow up to study the natural course of early postoperative lesions . Recurrent lesions were observed endoscopically in the neoterminal ileum within 1 year of surgery in 73 % of the patients , although only 20 % of the patients had symptoms . Three years after surgery , the endoscopic recurrence rate had increased to 85 % and symptomatic recurrence occurred in 34 % . The ultimate course of the disease was best predicted by the severity of the early postoperative lesions , as observed at ileoscopy . Clinical parameters that influenced outcome were preoperative disease activity , the indication for surgery , and the number of surgical resections . When patients were stratified for preoperative disease activity , the severity of lesions found at endoscopy remained a strong predictive factor for symptomatic recurrence . In 22 other patients su bmi tted to " curative " ileal resection and ileocolonic anastomosis , the segment to be used as neoterminal ileum was carefully examined during surgery , and two large biopsies were taken before making the anastomosis . An ileoscopy was performed 6 months after surgery . Although all patients had a macroscopically normal neoterminal ileum and 19 had entirely normal biopsies at the time of surgery , 21 patients were found at ileoscopy to have developed ileitis involving a 15-cm segment ( range , 4 - 30 cm ) , and 20 had unequivocal microscopic lesions on biopsies . These studies suggest that early lesions in the neoterminal ileum after Crohn 's resection do not originate from microscopic inflammation present in this bowel segment at the time of surgery . The early postoperative lesions in the neoterminal ileum seem to be a suitable model to study the pathogenesis of Crohn 's disease and also to evaluate new therapeutic modalities , either to prevent development of these early lesions or to treat progressive recurrence BACKGROUND / AIMS New lesions recur within weeks to months after ileal resection and ileocolonic anastomosis for Crohn 's ileitis . A double-blind controlled trial was performed using metronidazole to prevent recurrence after ileal resection . METHODS Sixty patients who underwent curative ileal resection and primary anastomosis were included within 1 week after surgery . Thirty patients received metronidazole ( 20 mg/kg body wt ) daily for 3 months , and 30 patients received placebo . Treatment was then discontinued . Nine patients dropped out during treatment , 7 in the metronidazole group and 2 in the placebo arm . RESULTS At 12 weeks , 21 of 28 patients ( 75 % ) in the placebo group had recurrent lesions in the neoterminal ileum as compared with 12 of 23 patients ( 52 % ) in the metronidazole group ( P = 0.09 ) . The incidence of severe endoscopic recurrence was significantly reduced by metronidazole ( 3 of 23 ; 13 % ) as compared with placebo ( 12 of 28 ; 43 % ; P = 0.02 ) . Patients in the metronidazole arm had more frequent side effects . Metronidazole therapy statistically reduced the clinical recurrence rates at 1 year ( 4 % vs. 25 % ) . Reductions at 2 years ( 26 % vs. 43 % ) and 3 years ( 30 % vs. 50 % ) were not significant . CONCLUSIONS Metronidazole therapy for 3 months decreases the severity of early recurrence of Crohn 's disease in the neoterminal ileum after resection and seems to delay symptomatic recurrence Objective The aim of the study was to compare azathioprine versus mesalazine tablets for the prevention of clinical recurrence in patients with postoperative Crohn 's disease ( CD ) with moderate or severe endoscopic recurrence . Methods This was a 1 year , double-blind , double-dummy , r and omised study which took place in 21 gastroenterology centres in Austria , the Czech Republic , Germany and Israel . The study participants were 78 adults with CD who had undergone resection with ileocolonic anastomosis in the preceding 6–24 months without subsequent clinical recurrence and with a Crohn 's disease activity index ( CDAI ) score < 200 , but with moderate or severe endoscopic recurrence . The study drugs were azathioprine 2.0–2.5 mg/kg/day or mesalazine 4 g/day over 1 year . The primary end point was therapeutic failure during 1 year , defined as a CDAI score ≥200 and an increase of ≥60 points from baseline , or study drug discontinuation due to lack of efficacy or intolerable adverse drug reaction . Results Treatment failure occurred in 22.0 % ( 9/41 ) of azathioprine-treated patients and 10.8 % ( 4/37 ) of mesalazine-treated patients , a difference of 11.1 % ( 95 % CI −5.0 % to 27.3 % , p=0.19 ) . Clinical recurrence was significantly less frequent with azathioprine versus mesalazine ( 0/41 ( 0 % ) vs 4/37 ( 10.8 % ) , p=0.031 ) , whereas study drug discontinuation due to adverse drug reactions only occurred in azathioprine-treated patients ( 9/41 ( 22.0 % ) vs 0 % , p=0.002 ) . The proportion of patients showing ≥1 point reduction in Rutgeerts score between baseline and month 12 was 63.3 % ( 19/30 ) and 34.4 % ( 11/32 ) in the azathioprine and mesalazine groups , respectively ( p=0.023 ) . Conclusions In this population of patients with postoperative CD at high risk of clinical recurrence , superiority for azathioprine versus mesalazine could not be demonstrated for therapeutic failure . Clinical trial registration number NCT00946946 Recurrence rate is high after operation for Crohn 's disease . A multicenter trial was performed to study the effect of radical or nonradical operation and of sulfasalazine prophylaxis versus placebo on postoperative recurrence rate in 232 patients with Crohn 's disease . Sixteen medical and surgical centers participated in the study , 7 operating radically and 9 nonradically . The follow-up period lasted 3 years , the allocation to drug treatment was r and omized and double blind . Recurrence was significantly less frequent and occurred later in patients who were operated nonradically . Patients on sulfasalazine prophylaxis had a better prognosis than on placebo . This effect was statistically significant in the first 2 years of treatment . Both strategies were additive : nonradical operation and sulfasalazine had the best prognosis , radical operation and placebo was worst . It is concluded that postoperative recurrence is best prevented by resecting nonradically and prescribing 3 g of sulfasalazine daily at least over 2 years BACKGROUND & AIMS No therapy has been shown to reliably prevent the evolution of postoperative recurrence of Crohn 's disease . The aim of the current trial was to compare 6-mercaptopurine ( 6-MP ) and mesalamine with placebo for the prevention of clinical , endoscopic , and radiographic recurrence of Crohn 's disease after resection and ileocolic anastomosis . METHODS Five centers r and omized 131 patients to receive 6-MP ( 50 mg ) , mesalamine  ( 3 g ) , or placebo daily in a double-blind , double-dummy trial . Patients had clinical assessment s at 7 weeks and then every 3 months ; colonoscopy at 6 , 12 , and 24 months ; and small bowel series at 12 and 24 months . End points were clinical , endoscopic , and radiographic recurrence rates at 24 months . RESULTS Clinical recurrence rates ( intent to treat ) by life-table analysis at 24 months were 50 % ( 95 % confidence interval [ CI ] , 34%-68 % ) , 58 % ( 95 % CI , 41%-75 % ) , and 77 % ( 95 % CI , 61%-91 % ) in patients receiving 6-MP , mesalamine , and placebo , respectively . Endoscopic recurrence rates were 43 % ( 95 % CI , 28%-63 % ) , 63 % ( 95 % CI , 47%-79 % ) , and 64 % ( 95 % CI , 46%-81 % ) , and radiographic recurrence rates were 33 % ( 95 % CI , 19%-54 % ) , 46 % ( 95 % CI , 29%-66 % ) , and 49 % ( 95 % CI , 30%-72 % ) , respectively . 6-MP was more effective than placebo ( P < 0.05 ) at preventing clinical and endoscopic recurrence over 2 years . Patient withdrawals result ed in 69 % of the study population evaluable for the clinical recurrence end point . CONCLUSIONS 6-MP , 50 mg daily , was more effective than placebo at preventing postoperative recurrence of Crohn 's disease and should be considered as a maintenance therapy after ileocolic resection Guidelines for clinical practice are intended to suggest preferable approaches to particular medical problems as established by interpretation and collation of scientifically valid research , derived from extensive review of published literature . When data that will withst and objective scrutiny are not available , a recommendation may be made based on a consensus of experts . Guidelines are intended to apply to the clinical situation for all physicians without regard to specialty . Guidelines are intended to be flexible , not necessarily indicating the only acceptable approach , and should be distinguished from st and ards of care that are inflexible and rarely violated . Given the wide range of choices in any health-care problem , the physician should select the course best suited to the individual patient and the clinical situation presented . These guidelines are developed under the auspices of the American College of Gastroenterology and its Practice Parameters Committee . Expert opinion is solicited from the outset for the document . The quality of evidence upon which a specific recommendation is based is as follows : Grade A : Homogeneous evidence from multiple well- design ed r and omized ( therapeutic ) or cohort ( descriptive ) controlled trials , each involving a number of participants to be of sufficient statistical power . Grade B : Evidence from at least one large well- design ed clinical trial with or without r and omization , from cohort or case – control analytic studies , or well- design ed meta- analysis . Grade C : Evidence based on clinical experience , descriptive studies , or reports of expert committees . The Committee review s guidelines in depth , with participation from experienced clinicians and others in related fields . The final recommendations are based on the data available at the time of the production of the document and may be up date d with pertinent scientific developments at a later time BACKGROUND St and ardized criteria for Crohn 's disease ( CD ) have only recently been developed , and prospect i ve community-based incidence studies have been performed only during the past 3 decades . Geographic variations in incidence may therefore be due to differences in study design . METHODS From 1 January 1990 to 31 December 1993 all new cases of CD in four counties in southeastern Norway were prospect ively registered . RESULTS A total of 225 new cases yielded an annual incidence of 5.8/10(5 ) , with the highest incidence in mixed rural-urban areas . A peak of 11.2/10(5 ) in the annual incidence was found for the age group 15 to 24 years , with no significant differences in the overall annual incidence by gender . An average duration of 6 months of disease before diagnosis was unchanged during the 4 years . About half of the patients had isolated colonic disease , and one-quarter had isolated small-bowel disease . CONCLUSIONS This study confirms the high incidence figures for Sc and inavia , with a particularly high incidence in mixed rural-urban areas . Ileocolonoscopy improves the accuracy of the diagnosis and of the determination of disease extent , which may have therapeutic implication s for the treatment and follow-up of patients In a prospect i ve multicentre study , 97 patients with Crohn 's disease and operated on by a radical excision of the Crohn-involved bowel were r and omly divided into two groups , one treated 33 weeks postoperatively by corticosteroids and Salazopyrin and the other without any medical treatment postoperatively . The patients in the two groups were followed up during three years after the operation and an X-ray of the bowel was yearly performed . Thirteen patients were excluded for different reasons , which means that 84 patients were left for the study . There was no statistically significant difference in the number of recurrences after one , two , or three years of observation time in the two groups of patients . There was a statistically significantly longer time between diagnosis and operation in the group of patients with recurrences than in patients with no recurrences . This might mean that patients with Crohn 's disease undergoing an early operation have a better chance of escaping recurrences BACKGROUND The clinical course and prognosis in ulcerative colitis ( UC ) and Crohn 's disease ( CD ) have been described in many studies , mostly retrospective . Such studies are hampered by problems such as inclusion over a long time period , proper definitions , incomplete case records , and out date d methods of diagnosis . In a prospect i ve study we identified 846 patients with inflammatory bowel disease ( IBD ) over a 4-year period from 1990 to 1993 . Uniform diagnostic and th 
    Output:
    
agent
***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: Eighty-nine patients who had been treated by ileal resection for Crohn 's disease between 1979 and 1984 were included in a prospect i ve cohort follow up to study the natural course of early postoperative lesions . Recurrent lesions were observed endoscopically in the neoterminal ileum within 1 year of surgery in 73 % of the patients , although only 20 % of the patients had symptoms . Three years after surgery , the endoscopic recurrence rate had increased to 85 % and symptomatic recurrence occurred in 34 % . The ultimate course of the disease was best predicted by the severity of the early postoperative lesions , as observed at ileoscopy . Clinical parameters that influenced outcome were preoperative disease activity , the indication for surgery , and the number of surgical resections . When patients were stratified for preoperative disease activity , the severity of lesions found at endoscopy remained a strong predictive factor for symptomatic recurrence . In 22 other patients su bmi tted to " curative " ileal resection and ileocolonic anastomosis , the segment to be used as neoterminal ileum was carefully examined during surgery , and two large biopsies were taken before making the anastomosis . An ileoscopy was performed 6 months after surgery . Although all patients had a macroscopically normal neoterminal ileum and 19 had entirely normal biopsies at the time of surgery , 21 patients were found at ileoscopy to have developed ileitis involving a 15-cm segment ( range , 4 - 30 cm ) , and 20 had unequivocal microscopic lesions on biopsies . These studies suggest that early lesions in the neoterminal ileum after Crohn 's resection do not originate from microscopic inflammation present in this bowel segment at the time of surgery . The early postoperative lesions in the neoterminal ileum seem to be a suitable model to study the pathogenesis of Crohn 's disease and also to evaluate new therapeutic modalities , either to prevent development of these early lesions or to treat progressive recurrence BACKGROUND / AIMS New lesions recur within weeks to months after ileal resection and ileocolonic anastomosis for Crohn 's ileitis . A double-blind controlled trial was performed using metronidazole to prevent recurrence after ileal resection . METHODS Sixty patients who underwent curative ileal resection and primary anastomosis were included within 1 week after surgery . Thirty patients received metronidazole ( 20 mg/kg body wt ) daily for 3 months , and 30 patients received placebo . Treatment was then discontinued . Nine patients dropped out during treatment , 7 in the metronidazole group and 2 in the placebo arm . RESULTS At 12 weeks , 21 of 28 patients ( 75 % ) in the placebo group had recurrent lesions in the neoterminal ileum as compared with 12 of 23 patients ( 52 % ) in the metronidazole group ( P = 0.09 ) . The incidence of severe endoscopic recurrence was significantly reduced by metronidazole ( 3 of 23 ; 13 % ) as compared with placebo ( 12 of 28 ; 43 % ; P = 0.02 ) . Patients in the metronidazole arm had more frequent side effects . Metronidazole therapy statistically reduced the clinical recurrence rates at 1 year ( 4 % vs. 25 % ) . Reductions at 2 years ( 26 % vs. 43 % ) and 3 years ( 30 % vs. 50 % ) were not significant . CONCLUSIONS Metronidazole therapy for 3 months decreases the severity of early recurrence of Crohn 's disease in the neoterminal ileum after resection and seems to delay symptomatic recurrence Objective The aim of the study was to compare azathioprine versus mesalazine tablets for the prevention of clinical recurrence in patients with postoperative Crohn 's disease ( CD ) with moderate or severe endoscopic recurrence . Methods This was a 1 year , double-blind , double-dummy , r and omised study which took place in 21 gastroenterology centres in Austria , the Czech Republic , Germany and Israel . The study participants were 78 adults with CD who had undergone resection with ileocolonic anastomosis in the preceding 6–24 months without subsequent clinical recurrence and with a Crohn 's disease activity index ( CDAI ) score < 200 , but with moderate or severe endoscopic recurrence . The study drugs were azathioprine 2.0–2.5 mg/kg/day or mesalazine 4 g/day over 1 year . The primary end point was therapeutic failure during 1 year , defined as a CDAI score ≥200 and an increase of ≥60 points from baseline , or study drug discontinuation due to lack of efficacy or intolerable adverse drug reaction . Results Treatment failure occurred in 22.0 % ( 9/41 ) of azathioprine-treated patients and 10.8 % ( 4/37 ) of mesalazine-treated patients , a difference of 11.1 % ( 95 % CI −5.0 % to 27.3 % , p=0.19 ) . Clinical recurrence was significantly less frequent with azathioprine versus mesalazine ( 0/41 ( 0 % ) vs 4/37 ( 10.8 % ) , p=0.031 ) , whereas study drug discontinuation due to adverse drug reactions only occurred in azathioprine-treated patients ( 9/41 ( 22.0 % ) vs 0 % , p=0.002 ) . The proportion of patients showing ≥1 point reduction in Rutgeerts score between baseline and month 12 was 63.3 % ( 19/30 ) and 34.4 % ( 11/32 ) in the azathioprine and mesalazine groups , respectively ( p=0.023 ) . Conclusions In this population of patients with postoperative CD at high risk of clinical recurrence , superiority for azathioprine versus mesalazine could not be demonstrated for therapeutic failure . Clinical trial registration number NCT00946946 Recurrence rate is high after operation for Crohn 's disease . A multicenter trial was performed to study the effect of radical or nonradical operation and of sulfasalazine prophylaxis versus placebo on postoperative recurrence rate in 232 patients with Crohn 's disease . Sixteen medical and surgical centers participated in the study , 7 operating radically and 9 nonradically . The follow-up period lasted 3 years , the allocation to drug treatment was r and omized and double blind . Recurrence was significantly less frequent and occurred later in patients who were operated nonradically . Patients on sulfasalazine prophylaxis had a better prognosis than on placebo . This effect was statistically significant in the first 2 years of treatment . Both strategies were additive : nonradical operation and sulfasalazine had the best prognosis , radical operation and placebo was worst . It is concluded that postoperative recurrence is best prevented by resecting nonradically and prescribing 3 g of sulfasalazine daily at least over 2 years BACKGROUND & AIMS No therapy has been shown to reliably prevent the evolution of postoperative recurrence of Crohn 's disease . The aim of the current trial was to compare 6-mercaptopurine ( 6-MP ) and mesalamine with placebo for the prevention of clinical , endoscopic , and radiographic recurrence of Crohn 's disease after resection and ileocolic anastomosis . METHODS Five centers r and omized 131 patients to receive 6-MP ( 50 mg ) , mesalamine  ( 3 g ) , or placebo daily in a double-blind , double-dummy trial . Patients had clinical assessment s at 7 weeks and then every 3 months ; colonoscopy at 6 , 12 , and 24 months ; and small bowel series at 12 and 24 months . End points were clinical , endoscopic , and radiographic recurrence rates at 24 months . RESULTS Clinical recurrence rates ( intent to treat ) by life-table analysis at 24 months were 50 % ( 95 % confidence interval [ CI ] , 34%-68 % ) , 58 % ( 95 % CI , 41%-75 % ) , and 77 % ( 95 % CI , 61%-91 % ) in patients receiving 6-MP , mesalamine , and placebo , respectively . Endoscopic recurrence rates were 43 % ( 95 % CI , 28%-63 % ) , 63 % ( 95 % CI , 47%-79 % ) , and 64 % ( 95 % CI , 46%-81 % ) , and radiographic recurrence rates were 33 % ( 95 % CI , 19%-54 % ) , 46 % ( 95 % CI , 29%-66 % ) , and 49 % ( 95 % CI , 30%-72 % ) , respectively . 6-MP was more effective than placebo ( P < 0.05 ) at preventing clinical and endoscopic recurrence over 2 years . Patient withdrawals result ed in 69 % of the study population evaluable for the clinical recurrence end point . CONCLUSIONS 6-MP , 50 mg daily , was more effective than placebo at preventing postoperative recurrence of Crohn 's disease and should be considered as a maintenance therapy after ileocolic resection Guidelines for clinical practice are intended to suggest preferable approaches to particular medical problems as established by interpretation and collation of scientifically valid research , derived from extensive review of published literature . When data that will withst and objective scrutiny are not available , a recommendation may be made based on a consensus of experts . Guidelines are intended to apply to the clinical situation for all physicians without regard to specialty . Guidelines are intended to be flexible , not necessarily indicating the only acceptable approach , and should be distinguished from st and ards of care that are inflexible and rarely violated . Given the wide range of choices in any health-care problem , the physician should select the course best suited to the individual patient and the clinical situation presented . These guidelines are developed under the auspices of the American College of Gastroenterology and its Practice Parameters Committee . Expert opinion is solicited from the outset for the document . The quality of evidence upon which a specific recommendation is based is as follows : Grade A : Homogeneous evidence from multiple well- design ed r and omized ( therapeutic ) or cohort ( descriptive ) controlled trials , each involving a number of participants to be of sufficient statistical power . Grade B : Evidence from at least one large well- design ed clinical trial with or without r and omization , from cohort or case – control analytic studies , or well- design ed meta- analysis . Grade C : Evidence based on clinical experience , descriptive studies , or reports of expert committees . The Committee review s guidelines in depth , with participation from experienced clinicians and others in related fields . The final recommendations are based on the data available at the time of the production of the document and may be up date d with pertinent scientific developments at a later time BACKGROUND St and ardized criteria for Crohn 's disease ( CD ) have only recently been developed , and prospect i ve community-based incidence studies have been performed only during the past 3 decades . Geographic variations in incidence may therefore be due to differences in study design . METHODS From 1 January 1990 to 31 December 1993 all new cases of CD in four counties in southeastern Norway were prospect ively registered . RESULTS A total of 225 new cases yielded an annual incidence of 5.8/10(5 ) , with the highest incidence in mixed rural-urban areas . A peak of 11.2/10(5 ) in the annual incidence was found for the age group 15 to 24 years , with no significant differences in the overall annual incidence by gender . An average duration of 6 months of disease before diagnosis was unchanged during the 4 years . About half of the patients had isolated colonic disease , and one-quarter had isolated small-bowel disease . CONCLUSIONS This study confirms the high incidence figures for Sc and inavia , with a particularly high incidence in mixed rural-urban areas . Ileocolonoscopy improves the accuracy of the diagnosis and of the determination of disease extent , which may have therapeutic implication s for the treatment and follow-up of patients In a prospect i ve multicentre study , 97 patients with Crohn 's disease and operated on by a radical excision of the Crohn-involved bowel were r and omly divided into two groups , one treated 33 weeks postoperatively by corticosteroids and Salazopyrin and the other without any medical treatment postoperatively . The patients in the two groups were followed up during three years after the operation and an X-ray of the bowel was yearly performed . Thirteen patients were excluded for different reasons , which means that 84 patients were left for the study . There was no statistically significant difference in the number of recurrences after one , two , or three years of observation time in the two groups of patients . There was a statistically significantly longer time between diagnosis and operation in the group of patients with recurrences than in patients with no recurrences . This might mean that patients with Crohn 's disease undergoing an early operation have a better chance of escaping recurrences BACKGROUND The clinical course and prognosis in ulcerative colitis ( UC ) and Crohn 's disease ( CD ) have been described in many studies , mostly retrospective . Such studies are hampered by problems such as inclusion over a long time period , proper definitions , incomplete case records , and out date d methods of diagnosis . In a prospect i ve study we identified 846 patients with inflammatory bowel disease ( IBD ) over a 4-year period from 1990 to 1993 . Uniform diagnostic and th 
    Output:
    