title: Differences between early and late readmissions among patients: a cohort study.
abstract: BACKGROUND
  Early and late readmissions may have different causal factors, requiring different prevention strategies.
  
  
  OBJECTIVE
  To determine whether predictors of readmission change within 30 days after discharge.
  
  
  METHODS
  Retrospective cohort study.
  
  
  METHODS
  Academic medical center.
  
  
  METHODS
  Patients admitted between 1 January 2009 and 31 December 2010.
  
  
  METHODS
  Factors related to the index hospitalization (acute illness burden, inpatient care process factors, and clinical indicators of instability at discharge) and unrelated factors (chronic illness burden and social determinants of health) and how they affect early readmissions (0 to 7 days after discharge) and late readmissions (8 to 30 days after discharge).
  
  
  RESULTS
  13 334 admissions, representing 8078 patients, were included in the analysis. Early readmissions were associated with markers of acute illness burden, including length of hospital stay (odds ratio [OR], 1.02 [95% CI, 1.00 to 1.03]) and whether a rapid response team was called for assessment (OR, 1.48 [CI, 1.15 to 1.89]); markers of chronic illness burden, including receiving a medication indicating organ failure (OR, 1.19 [CI, 1.02 to 1.40]); and social determinants of health, including barriers to learning (OR, 1.18 [CI, 1.01 to 1.38]). Early readmissions were less likely if a patient was discharged between 8:00 a.m. and 12:59 p.m. (OR, 0.76 [CI, 0.58 to 0.99]). Late readmissions were associated with markers of chronic illness burden, including receiving a medication indicating organ failure (OR, 1.24 [CI, 1.08 to 1.41]) or hemodialysis (OR, 1.61 [CI, 1.12 to 2.17]), and social determinants of health, including barriers to learning (OR, 1.24 [CI, 1.09 to 1.42]) and having unsupplemented Medicare or Medicaid (OR, 1.16 [CI, 1.01 to 1.33]).
  
  
  CONCLUSIONS
  Readmissions were ascertained at 1 institution.
  
  
  CONCLUSIONS
  The time frame of 30 days after hospital discharge may not be homogeneous. Causal factors and readmission prevention strategies may differ for the early versus late periods.
  
  
  BACKGROUND
  Health Resources and Services Administration, National Institute on Aging, National Institutes of Health, Harvard Catalyst, and Harvard University.
authors.forename: Kelly L
authors.initials: KL
authors.lastname: Graham
authors.forename: Elissa H
authors.initials: EH
authors.lastname: Wilker
authors.forename: Michael D
authors.initials: MD
authors.lastname: Howell
authors.forename: Roger B
authors.initials: RB
authors.lastname: Davis
authors.forename: Edward R
authors.initials: ER
authors.lastname: Marcantonio
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017281:Cost of Illness; D005260:Female; D006801:Humans; D007902:Length of Stay; D008297:Male; D008484:Medicaid; D006278:Medicare; D008875:Middle Aged; D009102:Multiple Organ Failure / Q000188:drug therapy; D010351:Patient Discharge; D010353:Patient Education as Topic; D010359:Patient Readmission / Q000706:statistics & numerical data*; D006435:Renal Dialysis; D012189:Retrospective Studies; D013997:Time Factors; D014481:United States