title: Hospital-acquired acute kidney injury and hospital readmission: a cohort study.
abstract: BACKGROUND
  Hospital-acquired acute kidney injury (AKI) is associated with increased mortality and resource consumption. Little is known about the association of AKI with short-term hospital readmissions.
  
  
  METHODS
  Retrospective cohort study.
  
  
  METHODS
  We investigated whether adult survivors of hospital-acquired AKI were at increased odds for early hospital readmission.
  
  
  METHODS
  The peak-to-nadir serum creatinine difference during the index hospitalization was used to define AKI according to the KDIGO (Kidney Disease: Improving Global Outcomes) classification and staging system.
  
  
  METHODS
  Multivariable logistic regression analyses examined the association of AKI with 30-, 60-, and 90-day hospital readmission, adjusting for age, sex, race, Charlson-Deyo comorbidity index score, acute hospital-related factors, common causes of hospitalization, and baseline estimated glomerular filtration rate.
  
  
  RESULTS
  3,345 (15%) of 22,001 included patients experienced AKI during the index hospitalization. Compared to the non-AKI group, the AKI group had a significantly higher 30-day hospital readmission rate (11% vs 15%; P<0.001), which persisted at 60 and 90 days. The AKI group also was more likely to be readmitted to the hospital within 30 days for cardiovascular-related conditions, mainly heart failure (P<0.001) and acute myocardial infarction (P=0.01). AKI associated independently with higher odds of 30-day hospital readmission (OR, 1.21; 95% CI, 1.08-1.36), which persisted at 60 (OR, 1.15; 95% CI, 1.03-1.27) and 90 days (adjusted OR, 1.13; 95% CI, 1.02-1.25). Results were attenuated in a propensity score-matched cohort of 5,912 patients.
  
  
  CONCLUSIONS
  Single-center study of mild forms of AKI; ascertainment bias and outcome misclassification due to the use of administrative codes.
  
  
  CONCLUSIONS
  Our results suggest that survivors of hospital-acquired AKI experience higher odds of early hospital readmission. Transitions of care services may be warranted for such patients to prevent readmissions and reduce health care costs.
authors.affiliation: Division of Nephrology, Department of Medicine, Kidney and Dialysis Research Laboratory, St. Elizabeth's Medical Center, Tufts University, Boston, MA; Department of Medicine, Tufts University School of Medicine, Tufts University, Boston, MA.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Koulouridis
authors.affiliation: The Institute for Clinical Research and Health Policy Studies, Tufts Medical Center, Tufts University, Boston, MA; Tufts Clinical and Translational Science Institute, Tufts University, Boston, MA.
authors.forename: Lori Lyn
authors.initials: LL
authors.lastname: Price
authors.affiliation: Division of Nephrology, Department of Medicine, Kidney and Dialysis Research Laboratory, St. Elizabeth's Medical Center, Tufts University, Boston, MA; Department of Medicine, Tufts University School of Medicine, Tufts University, Boston, MA.
authors.forename: Nicolaos E
authors.initials: NE
authors.lastname: Madias
authors.affiliation: Division of Nephrology, Department of Medicine, Kidney and Dialysis Research Laboratory, St. Elizabeth's Medical Center, Tufts University, Boston, MA; Department of Medicine, Tufts University School of Medicine, Tufts University, Boston, MA; Tufts Clinical and Translational Science Institute, Tufts University, Boston, MA. Electronic address: bertrand.jaber@steward.org.
authors.forename: Bertrand L
authors.initials: BL
authors.lastname: Jaber
mesh_terms: D058186:Acute Kidney Injury / Q000175:diagnosis* / Q000453:epidemiology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D006760:Hospitalization / Q000639:trends; D006801:Humans; D008297:Male; D008875:Middle Aged; D010359:Patient Readmission / Q000639:trends*; D012189:Retrospective Studies; D062606:Tertiary Care Centers / Q000639:trends*
keywords: Acute kidney injury (AKI); acute renal failure (ARF); care transition; hospital-acquired; re-hospitalization; readmission