title: Timing of discharge: a key to understanding the reason for readmission after colorectal surgery.
abstract: OBJECTIVE
  There is a growing interest in surgery regarding the balance between appropriate hospital length of stay (LOS) and prevention of unnecessary readmissions. This study examines the relationship between postoperative LOS and unplanned readmission after colorectal resection, exploring whether patients discharged earlier have different readmission risk profiles.
  
  
  METHODS
  Patients undergoing colorectal resection were selected by Common Procedural Terminology (CPT) code from the 2012 ACS National Surgical Quality Improvement Program (NSQIP) database. Patients were stratified by LOS quartile. Kaplan-Meier analysis was used to examine characteristics associated with 30-day unplanned readmission. Factors with a p < 0.1 were included in the Cox proportional hazards model. Subsequently, chi-square analysis compared LOS, patient, and perioperative factors with the primary reason for readmission. Factors with a p < 0.2 were included in a multivariable logistic regression for each readmission reason.
  
  
  RESULTS
  For 33,033 patients undergoing colorectal resection, the overall 30-day unplanned readmission rate was 11 %. After adjusting for patient and perioperative factors, a postoperative LOS ≥8 days was associated with a 55 % increase in the relative hazard of readmission. Patients with a ≤3-day LOS were more likely to be readmitted with ileus/obstruction (odds ratio (OR): 1.8, p = 0.001) and pain (OR: 2.2, p = 0.007). LOS was not significantly associated with readmission for intraabdominal infection or medical complications.
  
  
  CONCLUSIONS
  Patients with longer LOS and complicated hospital courses continue to be high risk post-discharge, while straightforward early discharges have a different readmission risk profile. More targeted readmission prevention strategies are critical to focusing resource utilization for colorectal surgery patients.
authors.affiliation: Surgical Health Outcomes and Research Enterprise, Department of Surgery, University of Rochester Medical Center, 601 Elmwood Ave., Box SURG, Rochester, NY, 14642, USA, Kristin_Kelly@URMC.rochester.edu.
authors.forename: Kristin N
authors.initials: KN
authors.lastname: Kelly
authors.forename: James C
authors.initials: JC
authors.lastname: Iannuzzi
authors.forename: Christopher T
authors.initials: CT
authors.lastname: Aquina
authors.forename: Christian P
authors.initials: CP
authors.lastname: Probst
authors.forename: Katia
authors.initials: K
authors.lastname: Noyes
authors.forename: John R T
authors.initials: JR
authors.lastname: Monson
authors.forename: Fergal J
authors.initials: FJ
authors.lastname: Fleming
mesh_terms: D000328:Adult; D000368:Aged; D003082:Colectomy / Q000009:adverse effects*; D005260:Female; D006801:Humans; D045823:Ileus / Q000209:etiology; D007415:Intestinal Obstruction / Q000209:etiology*; D059413:Intraabdominal Infections / Q000209:etiology; D007902:Length of Stay / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D010149:Postoperative Pain / Q000209:etiology; D010351:Patient Discharge / Q000706:statistics & numerical data*; D010359:Patient Readmission / Q000706:statistics & numerical data*; D012007:Rectum / Q000601:surgery*; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors