title: Risk factors for and timing of adverse events after total shoulder arthroplasty.
abstract: BACKGROUND
  Total shoulder arthroplasty (TSA) is a likely target for future bundled payment initiatives, necessitating accurate preoperative risk stratification. The purpose of this study was to identify risk factors for unplanned readmission and severe adverse events, to risk stratify TSA patients based on these risk factors, and to assess timing of complications after TSA.
  
  
  METHODS
  Data were collected from patients undergoing TSA from 2009 to 2014 in the American College of Surgeons National Surgical Quality Improvement Program. Bivariate and multivariate analyses of risk factors for severe adverse events or readmission were assessed. Patients were risk stratified, and timing of severe adverse events and cause of readmission were evaluated.
  
  
  RESULTS
  The analysis included 5801 TSA patients; 146 (2.5%) suffered severe adverse events, and 158 (2.7%) had a 30-day unplanned readmission. The most common severe adverse events were reoperation (40%), thrombolic event (deep venous thrombosis or pulmonary embolism; 14%), cardiac event (10%), and death (8.2%). Pneumonia (8.9%) and thrombolic event (7.6%) were the most common medically related causes, whereas dislocation (7.6%) and postoperative infection or wound complication (5.1%) were the most common surgical causes for readmission. Multivariate analysis identified inflammatory arthritis (P = .026), male gender (P = .019), age (P < .001), functional status (P = .024), and American Society of Anesthesiologists class 3/4 (P = .01) as independent predictors for unplanned 30-day readmission and all but inflammatory arthritis for severe adverse events (P ≤ .05 for all). Patients with ≥3 risk factors had an 11.56 (P = .002) and 3.43 (P = .013) times increased odds of unplanned readmission and severe adverse events occurring within 2 weeks after surgery, respectively, compared with patients with 0 risk factors.
  
  
  CONCLUSIONS
  Patients at high risk of TSA complications and readmission should be identified preoperatively to improve outcomes and to lower costs. Bundled payment initiatives must account for both patient- and procedure-related risk factors.
authors.affiliation: Department of Orthopaedic Surgery, Mount Sinai Hospital, New York, NY, USA. Electronic address: andrew.lovy@mountsinai.org.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Lovy
authors.affiliation: Department of Orthopaedic Surgery, Mount Sinai Hospital, New York, NY, USA.
authors.forename: Aakash
authors.initials: A
authors.lastname: Keswani
authors.affiliation: Department of Orthopaedic Surgery, Mount Sinai Hospital, New York, NY, USA.
authors.forename: Christina
authors.initials: C
authors.lastname: Beck
authors.affiliation: Department of Orthopaedic Surgery, Mount Sinai Hospital, New York, NY, USA.
authors.forename: James E
authors.initials: JE
authors.lastname: Dowdell
authors.affiliation: Department of Orthopaedic Surgery, Mount Sinai Hospital, New York, NY, USA.
authors.forename: Bradford O
authors.initials: BO
authors.lastname: Parsons
mesh_terms: D000368:Aged; D000072228:Arthroplasty, Replacement, Shoulder / Q000009:adverse effects*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D009518:New York / Q000453:epidemiology; D010359:Patient Readmission / Q000639:trends; D011183:Postoperative Complications / Q000453:epidemiology* / Q000601:surgery; D011379:Prognosis; D058996:Quality Improvement; D012086:Reoperation; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D012785:Shoulder Joint / Q000601:surgery*; D013997:Time Factors
keywords: Total shoulder arthroplasty; bundled payment; complications; length of stay; readmission; risk factors