title: Regional variation in anesthesia assistance during outpatient colonoscopy is not associated with differences in polyp detection or complication rates.
abstract: OBJECTIVE
  We investigated the rate and predictors of anesthesia assistance during outpatient colonoscopy and whether anesthesia assistance is associated with colonoscopy interventions and outcomes.
  
  
  METHODS
  We performed a retrospective cohort study using a 20% sample of Medicare administrative claims submitted during the 2003 calendar year. We analyzed data from 328,177 adults, 66 years old or older, who underwent outpatient colonoscopy examinations.
  
  
  RESULTS
  Overall, 8.7% of outpatient colonoscopies were performed with anesthesia assistance. In multivariate analysis, independent predictors of anesthesia assistance included black race, female sex, and a nonscreening indication; anesthesia assistance increased with median income and comorbidities. General and colorectal surgeons, fewer years in their practice, and nonhospital site of service were also significantly associated with anesthesia assistance. The strongest predictor of anesthesia assistance was the Medicare carrier, with odds ratios ranging from 0.22 (95% confidence interval: 0.12-0.43) for the Arkansas carrier (crude rate 0.9%) to 9.90 (95% confidence interval: 7.92-12.39) for the Empire carrier in New York area (crude rate 35.3%) compared with the Wisconsin carrier (crude rate 4.3%). There was also considerable variation among endoscopists; 75% of providers had no colonoscopies with anesthesia assistance recorded in their dataset, and 4.5% of providers had anesthesia assistance in at least three quarters of their examinations. Anesthesia assistance was not associated with the diagnosis of polyps, the performance of biopsy or polypectomy, or complications in multivariate analyses.
  
  
  CONCLUSIONS
  There are significant variations among regions and sites of service in anesthesia assistance during outpatient colonoscopies of Medicare beneficiaries. Although this variation has considerable economic implications, it was not associated with measures of patient risk or outcomes, such as polyp detection or procedure-related complications.
authors.affiliation: Northwest Center for Outcomes Research in Older Adults, VA Puget Sound Health Care System, Seattle, Washington; Division of Gastroenterology, Department of Medicine, University of Washington School of Medicine, Seattle, Washington. Electronic address: Jason.Dominitz@va.gov.
authors.forename: Jason A
authors.initials: JA
authors.lastname: Dominitz
authors.affiliation: Department of Family Medicine, University of Washington School of Medicine, Seattle, Washington.
authors.forename: Laura-Mae
authors.initials: LM
authors.lastname: Baldwin
authors.affiliation: Northwest Center for Outcomes Research in Older Adults, VA Puget Sound Health Care System, Seattle, Washington.
authors.forename: Pamela
authors.initials: P
authors.lastname: Green
authors.affiliation: Department of Health Services, University of Washington School of Medicine, Seattle, Washington.
authors.forename: William I
authors.initials: WI
authors.lastname: Kreuter
authors.affiliation: Division of Gastroenterology, Department of Medicine, University of Washington School of Medicine, Seattle, Washington.
authors.forename: Cynthia W
authors.initials: CW
authors.lastname: Ko
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000758:Anesthesia / Q000379:methods*; D003111:Colonic Polyps / Q000175:diagnosis* / Q000601:surgery; D003113:Colonoscopy / Q000379:methods*; D016001:Confidence Intervals; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D006278:Medicare / Q000706:statistics & numerical data; D010045:Outpatients; D010147:Pain Measurement; D010149:Postoperative Pain / Q000453:epidemiology* / Q000517:prevention & control; D011379:Prognosis; D012189:Retrospective Studies; D014481:United States / Q000453:epidemiology