title: Assessing the impact of screening colonoscopy on mortality in the medicare population.
abstract: BACKGROUND
  Some have recommended against routine screening for colorectal cancer (CRC) among patients ≥75 years of age, while others have suggested that screening colonoscopy (SC) is less beneficial for women than men. We estimated the expected benefits (decreased mortality from CRC) and harms (SC-related mortality) of SC based on sex, age, and comorbidity.
  
  
  OBJECTIVE
  To stratify older patients according to expected benefits and harms of SC based on sex, age, and comorbidity.
  
  
  METHODS
  Retrospective study using Medicare claims data.
  
  
  METHODS
  Medicare beneficiaries 67-94 years old with and without CRC.
  
  
  METHODS
  Life expectancy, CRC- and colonoscopy-attributable mortality rates across strata of sex, age, and comorbidity, pay-off time (i.e. the minimum time until benefits from SC exceeded harms), and life-years saved for every 100,000 SC.
  
  
  RESULTS
  Increasing age and comorbidity were associated with lower CRC-attributable mortality. Due to shorter life expectancy and CRC-attributable mortality, the benefits associated with SC were substantially lower among patients with greater comorbidity. Among men aged 75-79 years with no comorbidity, the number of life-years saved was 459 per 100,000 SC, while men aged 67-69 with ≥3 comorbidities had 81 life-years saved per 100,000 SC. There was no evidence that SC was less effective in women. Among men and women 75-79 with no comorbidity, number of life-years saved was 459 and 509 per 100,000 SC, respectively; among patients with ≥3 comorbidities, there was no benefit for either men or women.
  
  
  CONCLUSIONS
  Although the effectiveness of SC was equivalent for men and women, there was substantial variation in SC effectiveness within age groups, arguing against screening recommendations based solely on age.
authors.affiliation: Yale School of Medicine, Section of General Internal Medicine, New Haven, CT 06520, USA. cary.gross@yale.edu
authors.forename: Cary P
authors.initials: CP
authors.lastname: Gross
authors.forename: Pamela R
authors.initials: PR
authors.lastname: Soulos
authors.forename: Joseph S
authors.initials: JS
authors.lastname: Ross
authors.forename: Laura D
authors.initials: LD
authors.lastname: Cramer
authors.forename: Christopher
authors.initials: C
authors.lastname: Guerrero
authors.forename: Mary E
authors.initials: ME
authors.lastname: Tinetti
authors.forename: R Scott
authors.initials: RS
authors.lastname: Braithwaite
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003113:Colonoscopy / Q000379:methods / Q000592:standards*; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000401:mortality*; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods / Q000592:standards*; D006278:Medicare / Q000592:standards*; D011159:Population Surveillance / Q000379:methods; D012189:Retrospective Studies; D014481:United States / Q000453:epidemiology