Acute Kidney Injury Recovery Pattern and Subsequent Risk of CKD: An Analysis of Veterans Health Administration Data

Am J Kidney Dis. 2016 May;67(5):742-52. doi: 10.1053/j.ajkd.2015.10.019. Epub 2015 Dec 12.


Background: Studies suggest an association between acute kidney injury (AKI) and long-term risk for chronic kidney disease (CKD), even following apparent renal recovery. Whether the pattern of renal recovery predicts kidney risk following AKI is unknown.

Study design: Retrospective cohort.

Setting & participants: Patients in the Veterans Health Administration in 2011 hospitalized (> 24 hours) with at least 2 inpatient serum creatinine measurements, baseline estimated glomerular filtration rate > 60 mL/min/1.73 m², and no diagnosis of end-stage renal disease or non-dialysis-dependent CKD: 17,049 (16.3%) with and 87,715 without AKI.

Predictor: Pattern of recovery to creatinine level within 0.3 mg/dL of baseline after AKI: within 2 days (fast), in 3 to 10 days (intermediate), and no recovery by 10 days (slow or unknown).

Outcome: CKD stage 3 or higher, defined as 2 outpatient estimated glomerular filtration rates < 60 mL/min/1.73m² at least 90 days apart or CKD diagnosis, dialysis therapy, or transplantation.

Measurements: Risk for CKD was modeled using modified Poisson regression and time to death-censored CKD was modeled using Cox proportional hazards regression, both stratified by AKI stage.

Results: Most patients' AKI episodes were stage 1 (91%) and 71% recovered within 2 days. At 1 year, 18.2% had developed CKD (AKI, 31.8%; non-AKI, 15.5%; P < 0.001). In stage 1, the adjusted relative risk ratios for CKD stage 3 or higher were 1.43 (95% CI, 1.39-1.48), 2.00 (95% CI, 1.88-2.12), and 2.65 (95% CI, 2.51-2.80) for fast, intermediate, and slow/unknown recovery. A similar pattern was observed in subgroup analyses incorporating albuminuria and sensitivity analysis of death-censored time to CKD.

Limitations: Variable timing of follow-up and mostly male veteran cohort may limit generalizability.

Conclusions: Patients who develop AKI during a hospitalization are at substantial risk for the development of CKD by 1 year following hospitalization and timing of AKI recovery is a strong predictor, even for the mildest forms of AKI.

Keywords: AKI outcomes; Renal recovery; Veterans Administration (VA); acute kidney injury (AKI); acute on chronic kidney disease; chronic kidney disease (CKD); kidney function; recovery speed; renal complications; serum creatinine.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Acute Kidney Injury / blood
  • Acute Kidney Injury / epidemiology*
  • Acute Kidney Injury / physiopathology
  • Adult
  • African Americans / statistics & numerical data
  • Aged
  • Albuminuria / epidemiology*
  • Cohort Studies
  • Comorbidity
  • Creatinine / blood
  • Databases, Factual
  • Diabetes Mellitus / epidemiology
  • Disease Progression
  • Female
  • Hospitalization
  • Humans
  • Hypertension / epidemiology
  • Kidney Failure, Chronic / blood
  • Kidney Failure, Chronic / epidemiology*
  • Kidney Failure, Chronic / therapy
  • Kidney Transplantation
  • Length of Stay
  • Male
  • Middle Aged
  • Proportional Hazards Models
  • Recovery of Function*
  • Renal Dialysis
  • Renal Insufficiency, Chronic / blood
  • Renal Insufficiency, Chronic / epidemiology*
  • Respiration, Artificial / statistics & numerical data
  • Retrospective Studies
  • Risk Factors
  • Sepsis / epidemiology
  • United States / epidemiology
  • United States Department of Veterans Affairs
  • Whites / statistics & numerical data
  • Young Adult


  • Creatinine