title: The pen and the scalpel: effect of diffusion of information on nonclinical variations in surgical treatment.
abstract: BACKGROUND
  As information is disseminated about best practices, variations in patterns of care should diminish over time.
  
  
  OBJECTIVE
  To test the hypotheses that differences in rates of a surgical procedure are associated with type of insurance in an era of evolving practice guidelines and that insurance and site differences diminish with time as consensus guidelines disseminate among the medical community.
  
  
  METHODS
  We use lymph node dissection among women with ductal carcinoma in situ (DCIS) as an example of a procedure with uncertain benefit. Using a sample of 1051 women diagnosed from 1985 through 2000 at 2 geographic sites, we collected detailed demographic, clinical, pathologic, and treatment information through abstraction of multiple medical records. We specified multivariate logistic models with flexible functions of time and time interactions with insurance and treatment site to test hypotheses.
  
  
  RESULTS
  Lymph node dissection rates varied significantly according to site of treatment and insurance status after controlling for clinical, pathologic, treatment, and demographic characteristics. Rates of lymph node dissection decreased over time, and differences in lymph node dissection rates according to site and generosity of insurance were no longer significant by the end of the study period.
  
  
  CONCLUSIONS
  We have demonstrated that rates of a discretionary surgical procedure differ according to nonclinical factors, such as treatment site and type of insurance, and that such unwarranted variation decreases over time with diminishing uncertainty and in an era of diffusion of clinical guidelines.
authors.affiliation: Department of Medicine, Hematology/Oncology, University of Michigan, 300 North Ingalls, Ann Arbor, MI 48109, USA. jengrigg@umich.edu
authors.forename: Jennifer J
authors.initials: JJ
authors.lastname: Griggs
authors.forename: Melony E S
authors.initials: ME
authors.lastname: Sorbero
authors.forename: Gretchen M
authors.initials: GM
authors.lastname: Ahrendt
authors.forename: Azadeh
authors.initials: A
authors.lastname: Stark
authors.forename: Susanne
authors.initials: S
authors.lastname: Heininger
authors.forename: Heather T
authors.initials: HT
authors.lastname: Gold
authors.forename: Linda M
authors.initials: LM
authors.lastname: Schiffhauer
authors.forename: Andrew W
authors.initials: AW
authors.lastname: Dick
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000473:pathology / Q000601:surgery*; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000473:pathology / Q000601:surgery*; D004059:Diffusion of Innovation; D005260:Female; D019983:Guideline Adherence / Q000639:trends*; D006302:Health Services Research; D006801:Humans; D033181:Information Dissemination; D016015:Logistic Models; D008197:Lymph Node Excision / Q000639:trends*; D008408:Mastectomy / Q000639:trends; D008875:Middle Aged; D015999:Multivariate Analysis; D009518:New York; D018579:Patient Selection; D017410:Practice Guidelines as Topic; D010818:Practice Patterns, Physicians' / Q000639:trends*; D012051:Reimbursement Mechanisms / Q000706:statistics & numerical data; D012189:Retrospective Studies; D012959:Socioeconomic Factors