title: Geographic variation of endoscopic sinus surgery in the United States.
abstract: OBJECTIVE
  The objective of this study was to examine the rates and geographic variation of endoscopic sinus surgery (ESS) in a representative sample of the US working population.
  
  
  METHODS
  Observational cohort study using the MarketScan Commercial Claim and Encounters database.
  
  
  METHODS
  All patients who received ESS between 2009 and 2013 were included. The annual adjusted rates of ESS per 1,000 people were calculated for each US state. Geographic variations were evaluated using the extremal quotient (EQ), weighted coefficient of variation (CV), systematic component of variance (SCV), and empirical Bayes statistic. The χ(2) statistic tests was used to quantify variation of the adjusted ESS rates across states within the US.
  
  
  RESULTS
  The annual adjusted rate of ESS was 0.94 per 1,000 people in the US. South Dakota and Alabama were observed to have the highest rates of ESS, 1.80 and 1.69, respectively. Vermont and Arkansas were observed to have the lowest rates of ESS, 0.51 and 0.57, respectively. The mean EQ was 4.54, indicating a four- to fivefold difference between the highest (South Dakota) and lowest (Vermont) states. The mean CV was 31.4 and mean SCV was 10.1, which demonstrates very high variation.
  
  
  CONCLUSIONS
  This study observed very high geographic variation in the rates of ESS across the United States. Given that practice variation indicates the presence of potentially harmful and inefficient unwarranted care, outcomes from this study indicate a need to further evaluate the delivery of ESS to improve overall health system performance.
  
  
  METHODS
  2b.
authors.affiliation: Division of Otolaryngology-Head and Neck Surgery, Department of Surgery, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Luke
authors.initials: L
authors.lastname: Rudmik
authors.affiliation: Acclarent (c.e.h.), Menlo Park, California, U.S.A.
authors.forename: Chantal E
authors.initials: CE
authors.lastname: Holy
authors.affiliation: Division of Rhinology and Sinus Surgery, Oregon Sinus Center, Department of Otolaryngology-Head and Neck Surgery, Oregon Health and Science University, Portland, Oregon, U.S.A.
authors.forename: Timothy L
authors.initials: TL
authors.lastname: Smith
mesh_terms: D004724:Endoscopy / Q000706:statistics & numerical data*; D005500:Follow-Up Studies; D013517:Otorhinolaryngologic Surgical Procedures / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D012220:Rhinitis / Q000601:surgery*; D012852:Sinusitis / Q000601:surgery*; D014481:United States
keywords: Endoscopic sinus surgery; appropriateness; chronic rhinosinusitis; geographic variation; practice variation; quality of care; sinusitis