title: The volume-outcome relationship in laparoscopic cholecystectomy: a population-based study using propensity score matching.
abstract: BACKGROUND
  The volume-outcome relationship has been validated previously for surgical procedures and cancer treatments. However, no studies have longitudinally compared the relationships between volume and outcome, and none have systematically compared laparoscopic cholecystectomy (LC) surgery outcomes in Taiwan. This study purposed to explore the relationship between volume and hospital treatment cost after LC.
  
  
  METHODS
  This cohort study retrospectively analyzed 247,751 LCs performed from 1998 to 2009. Hospitals were classified as low-, medium-, and high-volume hospitals if their annual number of LCs were 1-29, 30-84, ≥85, respectively. Surgeons were classified as low-, medium-, and high-volume surgeons if their annual number of LCs were 1-10, 11-24, ≥25, respectively. Hierarchical linear regression model and propensity score were used to assess the relationship between volume and hospital treatment cost.
  
  
  RESULTS
  The mean hospital treatment cost was US $2,504.53, and the average hospital costs for high-volume hospitals/surgeons were 33/47% lower than those for low-volume hospitals and surgeons. When analyzed by propensity score, the hospital treatment cost differed significantly between high-volume hospitals/surgeons and low/medium-volume hospitals/surgeons (2,073.70 vs. 2,350.91/2,056.73 vs. 2,553.76, P < 0.001).
  
  
  CONCLUSIONS
  Analysis using a hierarchical linear regression model and propensity score found an association between high-volume hospitals and surgeons and hospital treatment cost in LC patients. Moreover, the significant factors associated with hospital resource utilization for this procedure include age, gender, comorbidity, hospital type, hospital volume, and surgeon volume. Additionally, analysis of the treatment strategies adopted at high-volume hospitals or by high-volume surgeons may improve overall hospital treatment cost.
authors.affiliation: Department of Healthcare Administration and Medical Informatics, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Hon-Yi
authors.initials: HY
authors.lastname: Shi
authors.forename: King-Teh
authors.initials: KT
authors.lastname: Lee
authors.forename: Chong-Chi
authors.initials: CC
authors.lastname: Chiu
authors.forename: Hao-Hsien
authors.initials: HH
authors.lastname: Lee
mesh_terms: D000368:Aged; D017081:Cholecystectomy, Laparoscopic / Q000191:economics / Q000706:statistics & numerical data*; D005260:Female; D017721:Hospital Costs; D061847:Hospitals, High-Volume / Q000706:statistics & numerical data*; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D057216:Propensity Score; D012189:Retrospective Studies; D013624:Taiwan; D016526:Workload