title: Drivers of readmissions in vascular surgery patients.
abstract: Postoperative readmissions are frequent in vascular surgery patients, but it is not clear which factors are the main drivers of readmissions. Specifically, the relative contributions of patient comorbidities vs those of operative factors and postoperative complications are unknown. We sought to study the multiple potential drivers of readmission and to create a model for predicting the risk of readmission in vascular patients.
  
  
  
  The 2012-2013 American College of Surgeons National Surgical Quality Improvement Program data set was queried for unplanned readmissions in 86,238 vascular patients. Multivariable forward selection logistic regression analysis was used to model the relative contributions of patient comorbidities, operative factors, and postoperative complications for readmission.
  
  
  
  The unplanned readmission rate was 9.3%. The preoperative model based on patient demographics and comorbidities predicted readmission risk with a low C index of .67; the top five predictors of readmission were American Society of Anesthesiologists class, preoperative open wound, inpatient operation, dialysis dependence, and diabetes mellitus. The postoperative model using operative factors and postoperative complications predicted readmission risk better (C index, .78); postoperative complications were the most significant predictor of readmission, overpowering patient comorbidities. Importantly, postoperative complications identified before discharge from the hospital were not a strong predictor of readmission as the model using predischarge postoperative complications had a similar C index to our preoperative model (.68). However, the inclusion of complications identified after discharge from the hospital appreciably improved the predictive power of the model (C index, .78). The top five predictors of readmission in the final model based on patient comorbidities and postoperative complications were postdischarge deep space infection, superficial surgical site infection, pneumonia, myocardial infection, and sepsis.
  
  
  
  Readmissions in vascular surgery patients are mainly driven by postoperative complications identified after discharge. Thus, efforts to reduce vascular readmissions focusing on inpatient hospital data may prove ineffective. Our study suggests that interventions to reduce vascular readmissions should focus on prompt identification of modifiable postdischarge complications.
authors.affiliation: Section of Vascular Surgery and Endovascular Therapy, Department of Surgery, University of Colorado Denver, Aurora, Colo. Electronic address: natalia.glebova@ucdenver.edu.
authors.forename: Natalia O
authors.initials: NO
authors.lastname: Glebova
authors.affiliation: Adult and Child Center for Outcomes Research and Delivery Science (ACCORDS), University of Colorado Denver, Aurora, Colo.
authors.forename: Michael
authors.initials: M
authors.lastname: Bronsert
authors.affiliation: Adult and Child Center for Outcomes Research and Delivery Science (ACCORDS), University of Colorado Denver, Aurora, Colo.
authors.forename: Karl E
authors.initials: KE
authors.lastname: Hammermeister
authors.affiliation: Section of Vascular Surgery and Endovascular Therapy, Department of Surgery, University of Colorado Denver, Aurora, Colo.
authors.forename: Mark R
authors.initials: MR
authors.lastname: Nehler
authors.affiliation: Section of Vascular Surgery and Endovascular Therapy, Department of Surgery, University of Colorado Denver, Aurora, Colo.
authors.forename: Douglas R
authors.initials: DR
authors.lastname: Gibula
authors.affiliation: Division of Vascular Surgery and Endovascular Therapy, Department of Surgery, Johns Hopkins Medical Institutes, Baltimore, Md.
authors.forename: Mahmoud B
authors.initials: MB
authors.lastname: Malas
authors.affiliation: Division of Vascular Surgery and Endovascular Therapy, Department of Surgery, Johns Hopkins Medical Institutes, Baltimore, Md.
authors.forename: James H
authors.initials: JH
authors.lastname: Black
authors.affiliation: Adult and Child Center for Outcomes Research and Delivery Science (ACCORDS), University of Colorado Denver, Aurora, Colo.
authors.forename: William G
authors.initials: WG
authors.lastname: Henderson
mesh_terms: D015897:Comorbidity; D016208:Databases, Factual; D006801:Humans; D016015:Logistic Models; D015999:Multivariate Analysis; D009203:Myocardial Infarction / Q000209:etiology / Q000628:therapy; D016017:Odds Ratio; D010359:Patient Readmission; D011014:Pneumonia / Q000209:etiology / Q000628:therapy; D011183:Postoperative Complications / Q000175:diagnosis / Q000209:etiology / Q000628:therapy*; D018570:Risk Assessment; D012307:Risk Factors; D018805:Sepsis / Q000209:etiology / Q000628:therapy; D013530:Surgical Wound Infection / Q000209:etiology / Q000628:therapy; D013997:Time Factors; D016896:Treatment Outcome; D014481:United States; D014656:Vascular Surgical Procedures / Q000009:adverse effects*