title: Incidence, Risk Factors, and Causes for Thirty-Day Unplanned Readmissions Following Primary Lower-Extremity Amputation in Patients with Diabetes.
abstract: BACKGROUND
  The Centers for Medicare & Medicaid Services targeted thirty-day readmissions as a quality-of-care measure. Hospitals can be penalized on unplanned readmissions. Given the frequency of amputation in diabetic patients and our changing health-care system, the purpose of this study was to determine the incidence, risk factors, and causes for unplanned thirty-day readmissions following primary lower-extremity amputation in diabetic patients.
  
  
  METHODS
  Patients with a diagnosis of diabetes undergoing primary lower-extremity amputation between 2002 and 2013 were retrospectively identified in a single-center patient database. Chart review determined patient factors including comorbidities, hemoglobin A1c level, amputation level, and demographic characteristics. Patients were divided into groups with and without unplanned readmission within thirty days postoperatively. Univariate and multivariate logistic regression analyses were used to compare cohorts and to identify variables associated with readmission.
  
  
  RESULTS
  Overall, forty-six (10.5%) of 439 diabetic patients undergoing primary lower-extremity amputation had an unplanned thirty-day readmission. The top reason for readmission was a major surgical event requiring reoperation (37.0%), followed by medical events (28.3%) and minor surgical events (28.3%). In the univariate analysis, discharge on antibiotics (p = 0.002), smoking (p = 0.003), chronic kidney disease (p = 0.002), peripheral vascular disease (p = 0.002), and higher Charlson Comorbidity Index (p = 0.001) were each associated with readmission. In the multivariate analysis, diagnosis of gangrene (odds ratio [OR], 2.95 [95% confidence interval (95% CI), 1.37 to 6.35]), discharge on antibiotics (OR, 4.48 [95% CI, 1.71 to 11.74]), smoking (OR, 3.22 [95% CI, 1.40 to 7.36]), chronic kidney disease (OR, 2.82 [95% CI, 1.30 to 6.15]), and peripheral vascular disease (OR, 2.47 [95% CI, 1.08 to 5.67]) were independently associated with readmission.
  
  
  CONCLUSIONS
  Thirty-day readmission rates following primary lower-extremity amputation in patients with diabetes were high at >10%. Both medical and surgical complications, many of which were unavoidable, contributed to readmission. Quality-reporting metrics should include these risk factors to avoid undeservedly penalizing surgeons and hospitals caring for this patient population.
  
  
  METHODS
  Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.
authors.affiliation: Department of Orthopaedic Surgery and Rehabilitation, University of Iowa Hospitals and Clinics, 200 Hawkins Drive, 01051 JPP, Iowa City, IA 52242. E-mail address for Z. Ries: Zachary-ries@uiowa.edu. E-mail address for C. Rungprai: Chamnanni-rungprai@uiowa.edu. E-mail address for B. Harpole: Bethany-harpole@uiowa.edu. E-mail address for O.-a. Phruetthiphat: Ongart-phr1@hotmail.com. E-mail address for Y. Gao: Yubo-gao@uiowa.edu. E-mail address for A. Pugely: Andrew-pugely@uiowa.edu. E-mail address for P. Phisitkul: Phinit-phisitkul@uiowa.edu.
authors.forename: Zachary
authors.initials: Z
authors.lastname: Ries
authors.affiliation: Department of Orthopaedic Surgery and Rehabilitation, University of Iowa Hospitals and Clinics, 200 Hawkins Drive, 01051 JPP, Iowa City, IA 52242. E-mail address for Z. Ries: Zachary-ries@uiowa.edu. E-mail address for C. Rungprai: Chamnanni-rungprai@uiowa.edu. E-mail address for B. Harpole: Bethany-harpole@uiowa.edu. E-mail address for O.-a. Phruetthiphat: Ongart-phr1@hotmail.com. E-mail address for Y. Gao: Yubo-gao@uiowa.edu. E-mail address for A. Pugely: Andrew-pugely@uiowa.edu. E-mail address for P. Phisitkul: Phinit-phisitkul@uiowa.edu.
authors.forename: Chamnanni
authors.initials: C
authors.lastname: Rungprai
authors.affiliation: Department of Orthopaedic Surgery and Rehabilitation, University of Iowa Hospitals and Clinics, 200 Hawkins Drive, 01051 JPP, Iowa City, IA 52242. E-mail address for Z. Ries: Zachary-ries@uiowa.edu. E-mail address for C. Rungprai: Chamnanni-rungprai@uiowa.edu. E-mail address for B. Harpole: Bethany-harpole@uiowa.edu. E-mail address for O.-a. Phruetthiphat: Ongart-phr1@hotmail.com. E-mail address for Y. Gao: Yubo-gao@uiowa.edu. E-mail address for A. Pugely: Andrew-pugely@uiowa.edu. E-mail address for P. Phisitkul: Phinit-phisitkul@uiowa.edu.
authors.forename: Bethany
authors.initials: B
authors.lastname: Harpole
authors.affiliation: Department of Orthopaedic Surgery and Rehabilitation, University of Iowa Hospitals and Clinics, 200 Hawkins Drive, 01051 JPP, Iowa City, IA 52242. E-mail address for Z. Ries: Zachary-ries@uiowa.edu. E-mail address for C. Rungprai: Chamnanni-rungprai@uiowa.edu. E-mail address for B. Harpole: Bethany-harpole@uiowa.edu. E-mail address for O.-a. Phruetthiphat: Ongart-phr1@hotmail.com. E-mail address for Y. Gao: Yubo-gao@uiowa.edu. E-mail address for A. Pugely: Andrew-pugely@uiowa.edu. E-mail address for P. Phisitkul: Phinit-phisitkul@uiowa.edu.
authors.forename: Ong-Art
authors.initials: OA
authors.lastname: Phruetthiphat
authors.affiliation: Department of Orthopaedic Surgery and Rehabilitation, University of Iowa Hospitals and Clinics, 200 Hawkins Drive, 01051 JPP, Iowa City, IA 52242. E-mail address for Z. Ries: Zachary-ries@uiowa.edu. E-mail address for C. Rungprai: Chamnanni-rungprai@uiowa.edu. E-mail address for B. Harpole: Bethany-harpole@uiowa.edu. E-mail address for O.-a. Phruetthiphat: Ongart-phr1@hotmail.com. E-mail address for Y. Gao: Yubo-gao@uiowa.edu. E-mail address for A. Pugely: Andrew-pugely@uiowa.edu. E-mail address for P. Phisitkul: Phinit-phisitkul@uiowa.edu.
authors.forename: Yubo
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Department of Orthopaedic Surgery and Rehabilitation, University of Iowa Hospitals and Clinics, 200 Hawkins Drive, 01051 JPP, Iowa City, IA 52242. E-mail address for Z. Ries: Zachary-ries@uiowa.edu. E-mail address for C. Rungprai: Chamnanni-rungprai@uiowa.edu. E-mail address for B. Harpole: Bethany-harpole@uiowa.edu. E-mail address for O.-a. Phruetthiphat: Ongart-phr1@hotmail.com. E-mail address for Y. Gao: Yubo-gao@uiowa.edu. E-mail address for A. Pugely: Andrew-pugely@uiowa.edu. E-mail address for P. Phisitkul: Phinit-phisitkul@uiowa.edu.
authors.forename: Andrew
authors.initials: A
authors.lastname: Pugely
authors.affiliation: Department of Orthopaedic Surgery and Rehabilitation, University of Iowa Hospitals and Clinics, 200 Hawkins Drive, 01051 JPP, Iowa City, IA 52242. E-mail address for Z. Ries: Zachary-ries@uiowa.edu. E-mail address for C. Rungprai: Chamnanni-rungprai@uiowa.edu. E-mail address for B. Harpole: Bethany-harpole@uiowa.edu. E-mail address for O.-a. Phruetthiphat: Ongart-phr1@hotmail.com. E-mail address for Y. Gao: Yubo-gao@uiowa.edu. E-mail address for A. Pugely: Andrew-pugely@uiowa.edu. E-mail address for P. Phisitkul: Phinit-phisitkul@uiowa.edu.
authors.forename: Phinit
authors.initials: P
authors.lastname: Phisitkul
mesh_terms: D000328:Adult; D000368:Aged; D000671:Amputation, Surgical / Q000009:adverse effects*; D048909:Diabetes Complications / Q000150:complications* / Q000601:surgery*; D005260:Female; D006801:Humans; D015994:Incidence; D035002:Lower Extremity; D008297:Male; D008875:Middle Aged; D010359:Patient Readmission; D012086:Reoperation; D012189:Retrospective Studies; D012307:Risk Factors