title: Hospital readmission rates after surgical treatment of primary and metastatic tumors of the spine.
abstract: METHODS
  Retrospective cohort study.
  
  
  OBJECTIVE
  This study aimed to identify the rates and causes of unplanned hospital readmission at 30 days and 1 year after surgical treatment of primary and metastatic spinal tumors.
  
  
  BACKGROUND
  Primary spine tumors and non-spine tumors metastatic to the spine can represent complex problems for surgical treatment, but surgical intervention can provide significant patients with significant improvements in quality of life. However, recent emphasis on decreasing the cost of health care has led to a focus on quality measures such as hospital readmission rates.
  
  
  METHODS
  At a large referral spine center between 2005 and 2011, 197 patients with primary (n = 33) or metastatic (n = 164) tumors of the spine were enrolled. Hospital readmissions within 1 year were reviewed. Kaplan-Meier analysis was performed to estimate unplanned hospital readmission rates, and risk factors were evaluated using a Cox proportional hazards model.
  
  
  RESULTS
  Unplanned hospital readmission rates were 6.1% and 16.8% at 30 days for primary and metastatic tumors (P = 0.126), respectively, and 27.5% and 37.8% at 1 year (P = 0.262). Metastatic tumors with aggressive biology (i.e., lung, osteosarcoma, stomach, bladder, esophagus, pancreas) caused higher rates of readmission than other types of metastatic tumors. One-third of readmissions were due to recurrent disease, whereas 23.3% were due to surgical complications and 43.3% due to medical complications. Numerous medical comorbidities increased the risk of unplanned hospital readmission.
  
  
  CONCLUSIONS
  Unplanned hospital readmissions after surgical intervention for spine tumors are common, and patients with aggressive metastatic tumors are at increased risk. In addition, comorbid medical problems are important risk factors that increase the chance that a patient will require hospital readmission within 1 year.
  
  
  METHODS
  3.
authors.affiliation: From the Departments of *Orthopaedic Surgery and †Neurological Surgery, University of California San Francisco, San Francisco.
authors.forename: William W
authors.initials: WW
authors.lastname: Schairer
authors.forename: Alexandra
authors.initials: A
authors.lastname: Carrer
authors.forename: David C
authors.initials: DC
authors.lastname: Sing
authors.forename: Dean
authors.initials: D
authors.lastname: Chou
authors.forename: Praveen V
authors.initials: PV
authors.lastname: Mummaneni
authors.forename: Serena S
authors.initials: SS
authors.lastname: Hu
authors.forename: Sigurd H
authors.initials: SH
authors.lastname: Berven
authors.forename: Shane
authors.initials: S
authors.lastname: Burch
authors.forename: Bobby
authors.initials: B
authors.lastname: Tay
authors.forename: Vedat
authors.initials: V
authors.lastname: Deviren
authors.forename: Christopher
authors.initials: C
authors.lastname: Ames
mesh_terms: D000328:Adult; D000368:Aged; D016009:Chi-Square Distribution; D015897:Comorbidity; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D010027:Osteotomy / Q000009:adverse effects*; D010359:Patient Readmission; D011183:Postoperative Complications / Q000209:etiology* / Q000628:therapy; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D012495:San Francisco; D013125:Spinal Neoplasms / Q000473:pathology / Q000556:secondary / Q000601:surgery*; D013997:Time Factors; D016896:Treatment Outcome