title: Lower gastrointestinal bleeding:  incidence, etiology, and outcomes in a population-based setting.
abstract: OBJECTIVE
  To investigate the incidence and outcomes of acute lower gastrointestinal bleeding (ALGIB) in a population-based setting and examine the role of drugs potentially associated with GIB.
  
  
  METHODS
  The study was prospective and population based. The cohort included all patients who underwent colonoscopy during the year 2010 at the National University Hospital of Iceland. Indications for endoscopies and drug history were recorded in a systematic manner. The inclusion criteria were overt bleeding leading to hospitalization or occurring in hospitalized patients. The use of NSAIDs, low-dose aspirin, warfarin, selective serotonin receptor inhibitors, and bisphosphonates before GIB was also checked in a Pharmaceutical Database covering all drug prescriptions in the country. A control group included patients who underwent colonoscopy during the study period and did not have GIB.
  
  
  RESULTS
  Altogether, 1134 patients underwent 1275 colonoscopies. Overall, 163 patients had ALGIB. The crude incidence for ALGIB was 87/100 000 inhabitants/year. The most common findings were diverticulosis (23%) and ischemic colitis (16%). A total of 7.4% of individuals had endoscopic therapy and none had undergone surgery. Two (1.2%) patients died because of ALGIB, both with severe comorbidities. Overall, 19% with ALGIB were on NSAIDs versus 9% in nonbleeders (P=0.0096); 37% with ALGIB were on low-dose aspirin versus 25% in nonbleeders (P=0.0222).
  
  
  CONCLUSIONS
  The incidence for ALGIB is the highest reported to date. The most common reasons for ALGIB were diverticulosis and ischemic colitis. Mortality during hospitalization was very low. NSAIDs and low-dose aspirin seem to increase the risk for ALGIB.
authors.affiliation: Department of Internal Medicine, Section of Gastroenterology and Hepatology, National University Hospital, Reykjavik, Iceland.
authors.forename: Jóhann P
authors.initials: JP
authors.lastname: Hreinsson
authors.forename: Sveinn
authors.initials: S
authors.lastname: Gumundsson
authors.forename: Evangelos
authors.initials: E
authors.lastname: Kalaitzakis
authors.forename: Einar S
authors.initials: ES
authors.lastname: Björnsson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000009:adverse effects; D001241:Aspirin / Q000009:adverse effects; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D017091:Colitis, Ischemic / Q000175:diagnosis / Q000453:epidemiology* / Q000401:mortality / Q000628:therapy; D003113:Colonoscopy; D015897:Comorbidity; D004240:Diverticulum / Q000175:diagnosis / Q000453:epidemiology* / Q000401:mortality / Q000628:therapy; D005260:Female; D006471:Gastrointestinal Hemorrhage / Q000139:chemically induced / Q000175:diagnosis / Q000453:epidemiology* / Q000401:mortality / Q000628:therapy; D017052:Hospital Mortality; D006785:Hospitals, University; D006801:Humans; D007055:Iceland / Q000453:epidemiology; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D012307:Risk Factors; D055815:Young Adult
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D001241:Aspirin