title: Surveillance colonoscopy in elderly patients: a retrospective cohort study.
abstract: OBJECTIVE
  The risks and benefits of surveillance colonoscopy in elderly patients have not been well characterized.
  
  
  OBJECTIVE
  To investigate the relative impact of surveillance colonoscopy in elderly patients compared with a reference cohort.
  
  
  METHODS
  Retrospective cohort study from 2001 through 2010 of patients 50 years and older undergoing surveillance colonoscopy for a history of colorectal cancer (CRC) or adenomatous polyps at an integrated health care system in southern California. Patients were followed up from the surveillance examination until CRC diagnosis, death, disenrollment, IBD diagnosis, or study end date (December 31, 2010).
  
  
  METHODS
  The primary outcome measure was incidence of CRC detected following surveillance colonoscopy. The secondary outcome was risk of procedure defined as postprocedure hospitalization within 30 days. Cox regression and multivariable logistic regression analyses were used to determine the impact of age on CRC incidence on surveillance examination as well as postprocedure hospitalization, respectively.
  
  
  RESULTS
  The study cohort included 4834 elderly patients (age ≥75 years; 55.8% male) (median surveillance age, 79 years) and 22 929 individuals in the reference group (age 50-74 years; 57.7% male) (median surveillance age, 63 years). A total of 373 cancers were detected following surveillance colonoscopy (368 in the reference group and 5 among the elderly patients). There were a total of 711 postprocedure hospitalizations (184 in the reference group and 527 among the elderly patients). The CRC incidence among elderly patients undergoing surveillance was 0.24 per 1000 person-years vs 3.61 per 1000 person-years in the reference population (P < .001). In Cox regression analysis, the hazard ratio for CRC in the elderly patients compared with the reference group was 0.06 (95% CI, 0.02-0.13) (P < .001) after adjusting for comorbid illness, sex, and race/ethnicity. In logistic regression analysis, age 75 years and older was independently associated with increased risk of postprocedure hospitalization (adjusted odds ratio, 1.28 [95% CI, 1.07-1.53]; P = .006). Charlson score of 2 was also independently associated with increased risk of postprocedure hospitalization (adjusted odds ratio, 2.54 [95% CI, 2.06-3.14]; P < .001).
  
  
  CONCLUSIONS
  A low incidence of CRC and relatively high rate of postprocedure hospitalization were found among elderly patients undergoing surveillance colonoscopy. Recommendations for ongoing surveillance in the elderly population should take into consideration the impact of comorbid illness and increasing age on the anticipated risks and benefits of colonoscopy.
authors.affiliation: Department of Internal Medicine, Kaiser Permanente Los Angeles Medical Center, Los Angeles, California.
authors.forename: An Hong
authors.initials: AH
authors.lastname: Tran
authors.affiliation: Department of Research and Evaluation, Kaiser Permanente Southern California, Pasadena.
authors.forename: Eunis Wai
authors.initials: EW
authors.lastname: Man Ngor
authors.affiliation: Division of Gastroenterology, Kaiser Permanente Los Angeles Medical Center, Los Angeles, California4Center for Digestive Health Research, Southern California Permanente Medical Group, Los Angeles.
authors.forename: Bechien U
authors.initials: BU
authors.lastname: Wu
mesh_terms: D000367:Age Factors; D000368:Aged; D002140:California / Q000453:epidemiology; D015331:Cohort Studies; D003113:Colonoscopy / Q000009:adverse effects* / Q000706:statistics & numerical data*; D015179:Colorectal Neoplasms / Q000453:epidemiology* / Q000517:prevention & control*; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D015994:Incidence; D053208:Kaplan-Meier Estimate; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011159:Population Surveillance / Q000379:methods; D016016:Proportional Hazards Models; D012189:Retrospective Studies