title: Impact of hepatectomy surgical complexity on outcomes and hospital quality rankings.
abstract: BACKGROUND
  There is substantial variation in the surgical complexity of hepatectomy. Currently, the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) risk adjusts for hospital quality comparisons using only the primary procedure code. Our objectives were to (1) assess the association between secondary procedures and complications; (2) assess model performance with inclusion of surgical complexity adjustment; and (3) examine whether secondary procedures affect hospital quality rankings.
  
  
  METHODS
  Using ACS NSQIP (2007-2012), patients undergoing hepatectomy were identified. Secondary procedure codes and total work relative value units (RVUs) were used to approximate procedural complexity. The effect of procedural complexity variables on outcomes and hospital quality rankings were examined using hierarchical models.
  
  
  RESULTS
  Among 11,826 patients who underwent hepatectomy at 261 hospitals, 32.8 % underwent at least one secondary procedure. Serious morbidity occurred in 18.0 % of patients. Seven of nine secondary procedures were significantly associated with death or serious morbidity on multivariable analysis. Model performance improved when secondary procedure categories were included, and secondary procedure categories outperformed total RVUs. The C-statistic for death or serious morbidity was 0.689 in the standard NSQIP model, 0.703 when total RVU was included, and 0.718 when secondary procedure categories were included. Of the 26 hospitals that were poor performers for death or serious morbidity using the standard ACS NSQIP model, three became average performers when secondary procedure categories were included in the model.
  
  
  CONCLUSIONS
  Secondary procedures are associated with an increased risk of postoperative complications. Inclusion of secondary procedure code categories in research and risk prediction models should be considered for hepatectomy.
authors.affiliation: Division of Research and Optimal Patient Care, American College of Surgeons, Chicago, IL, USA, jlparuch@gmail.com.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Paruch
authors.forename: Ryan P
authors.initials: RP
authors.lastname: Merkow
authors.forename: David J
authors.initials: DJ
authors.lastname: Bentrem
authors.forename: Clifford Y
authors.initials: CY
authors.lastname: Ko
authors.forename: Mitchell C
authors.initials: MC
authors.lastname: Posner
authors.forename: Mark E
authors.initials: ME
authors.lastname: Cohen
authors.forename: Karl Y
authors.initials: KY
authors.lastname: Bilimoria
authors.forename: Sharon M
authors.initials: SM
authors.lastname: Weber
mesh_terms: D000368:Aged; D005260:Female; D006498:Hepatectomy / Q000009:adverse effects* / Q000401:mortality / Q000706:statistics & numerical data; D006761:Hospitals / Q000592:standards*; D006801:Humans; D007902:Length of Stay / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D017063:Outcome Assessment, Health Care / Q000706:statistics & numerical data*; D010359:Patient Readmission / Q000706:statistics & numerical data; D015895:Relative Value Scales; D012086:Reoperation / Q000706:statistics & numerical data; D020379:Risk Adjustment; D018805:Sepsis / Q000209:etiology; D013514:Surgical Procedures, Operative / Q000706:statistics & numerical data; D013530:Surgical Wound Infection / Q000209:etiology