title: An evaluation of differences in risk factors for individual types of surgical site infections after colon surgery.
abstract: BACKGROUND
  Most studies and national programs aggregate the different types of surgical site infections (SSIs) potentially masking and misattributing risk. Determining that risk factors for superficial, deep, and organ space SSIs are unique is essential to improve SSI rates.
  
  
  METHODS
  This cohort study utilized data of 59,365 patients who underwent colon resection at hospitals participating in the American College of Surgeons National Surgical Quality Improvement Program from 2007 to 2009. Four independent, multivariable, predictive models were developed to assess the unique associations between risk factors and each SSI group: Superficial, deep, organ space, and an aggregate of all 3 types of SSIs.
  
  
  RESULTS
  Overall, 13% of colon cases developed SSIs: Superficial (8%), deep (1.4%), and organ space (3.8%). Each model was different. Morbidly obese patients were more likely to develop SSIs than normal weight patients across all models; however, risk factors common to all models (eg, body mass index [BMI], duration of operation, wound class, laparoscopic approach) had very different levels of risk. Unique risks for superficial SSIs include diabetes, chronic obstructive pulmonary disease, and dyspnea. Deep SSIs had the greatest magnitude of association with BMI and the greatest incidence of wound disruption (19.8%). Organ space SSIs were often owing to anastomotic leaks and were uniquely associated with disseminated cancer, preoperative dialysis, preoperative radiation treatment, and a bleeding disorder, suggesting a physically frail or compromised patient may put the anastomosis at risk.
  
  
  CONCLUSIONS
  Risk factors for superficial, deep, and organ space SSI differ. More effective prevention strategies may be developed by reporting and examining each type of SSI separately.
authors.affiliation: University of Texas at MD Anderson Cancer Center, Houston, TX. Electronic address: cgsegal@mdanderson.org.
authors.forename: Cynthia G
authors.initials: CG
authors.lastname: Segal
authors.affiliation: The University of Texas School of Public Health, Houston, TX.
authors.forename: Dorothy K
authors.initials: DK
authors.lastname: Waller
authors.affiliation: The University of Texas School of Public Health, Houston, TX.
authors.forename: Barbara
authors.initials: B
authors.lastname: Tilley
authors.affiliation: The University of Texas School of Public Health, Houston, TX.
authors.forename: Linda
authors.initials: L
authors.lastname: Piller
authors.affiliation: Surgical Outcomes and Quality Improvement Center, Feinberg School of Medicine, Northwestern University, Evanston, IL.
authors.forename: Karl
authors.initials: K
authors.lastname: Bilimoria
mesh_terms: D000368:Aged; D003082:Colectomy / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D058996:Quality Improvement; D012189:Retrospective Studies; D012307:Risk Factors; D013530:Surgical Wound Infection / Q000209:etiology*