title: Hospital-based acute care after outpatient colonoscopy: implications for quality measurement in the ambulatory setting.
abstract: BACKGROUND
  Ambulatory surgery centers now report immediate hospital transfer rates as a measure of quality. For patients undergoing colonoscopy, this measure may fail to capture adverse events, which occur after discharge yet still require a hospital-based acute care encounter.
  
  
  OBJECTIVE
  We conducted this study to estimate rates of immediate hospital transfer and hospital-based acute care following outpatient colonoscopy performed in ambulatory surgery centers.
  
  
  METHODS
  Using state ambulatory surgery databases from the 2009-2010 Healthcare Cost and Utilization Project, we identified adult patients who underwent colonoscopy. Immediate hospital transfer and overall acute health care utilization in the 14 days following colonoscopy was determined from corresponding inpatient, ambulatory surgery, and emergency department databases. To compare rates across centers while accounting for differences in patient populations, we calculated risk-standardized rates using hierarchical generalized linear modeling.
  
  
  RESULTS
  The final sample included 1,137,381 colonoscopy discharges from 1019 centers. At the ambulatory surgery center level, the median risk-standardized hospital transfer rate was 0.0% (interquartile range=0.0%), whereas the hospital-based acute care rate was 2.1% (interquartile range=0.6%), with few centers (N=36) having no observed encounters. No correlation was noted between the risk-standardized hospital transfer and hospital-based acute care rates (volume weighted correlation coefficient=0.04, P=0.16).
  
  
  CONCLUSIONS
  Patients more frequently experience hospital-based acute care encounters after colonoscopy than the need for immediate hospital transfer. Broadening existing quality measures to include hospital-based acute care in the postdischarge period may provide a more complete measure of quality.
authors.affiliation: *Department of Surgery, Boonshoft School of Medicine, Wright State University, Dayton, OH †Center for Outcomes Research and Evaluation ‡Robert Wood Johnson Foundation Clinical Scholars Program, Section of General Internal Medicine, and Cancer Outcomes Policy and Effectiveness Research (COPPER) Center, Yale University School of Medicine, New Haven, CT.
authors.forename: Justin P
authors.initials: JP
authors.lastname: Fox
authors.forename: Deepika D'Cunha
authors.initials: DD
authors.lastname: Burkardt
authors.forename: Isuru
authors.initials: I
authors.lastname: Ranasinghe
authors.forename: Cary P
authors.initials: CP
authors.lastname: Gross
mesh_terms: D000368:Aged; D000556:Ambulatory Surgical Procedures / Q000009:adverse effects*; D003113:Colonoscopy / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010360:Patient Transfer / Q000706:statistics & numerical data*; D011183:Postoperative Complications / Q000453:epidemiology*; D019984:Quality Indicators, Health Care; D011787:Quality of Health Care; D012189:Retrospective Studies; D014481:United States