title: Frailty as a Predictor of Acute Kidney Injury in Hospitalized Elderly Patients: A Single Center, Retrospective Cohort Study.
abstract: BACKGROUND
  Elderly patients have an increased risk for acute kidney injury (AKI). However, few studies have reported on predictors for AKI in geriatric patients. Therefore, we aimed at determining the effect of frailty as a predictor of AKI.
  
  
  METHODS
  We retrospectively enrolled 533 hospitalized elderly patients (aged ≥ 65 years) who had their creatinine levels measured (≥ 1 measurement) during admission for a period of 1 year (2013) and conducted a comprehensive geriatric assessment (CGA) within 1 year before the index hospitalization. We examined five variables (activity of daily living [ADL] and instrumental ADL dependence, dementia, nutrition, and polypharmacy) from CGA. We categorized the patients into 3 groups according to the tertile of aggregate frailty scores: Group 1, score 1-2; Group 2, score 3-4; Group 3, score 5-8).
  
  
  RESULTS
  Fifty-four patients (10.1%) developed AKI (median duration, 4 days). The frailest group (Group 3) showed an increased risk of AKI as compared to Group 1, (hazard ratio [HR] = 3.536, P = 0.002). We found that discriminatory accuracy for AKI improved with the addition of the tertile of aggregate frailty score to covariates (area under the receiver operator characteristics curves [AUROC] 0.641, AUROC 0.739, P = 0.004). Forty-six patients (8.6%) were transferred to nursing facilities and 477 patients (89.5%) were discharged home. The overall 90-day and 1-year mortality for elderly inpatients were 7.9% and 26.3%. The frailest group also demonstrated an increased risk of discharge to nursing facilities, and 90-day and 1-year mortality as compared to Group 1, independent of AKI severity (nursing facilities: odd ratio = 4.843, P = 0.002; 90-day mortality: HR = 6.555, P = 0.002; 1-year mortality: HR = 3.249, P = 0.001).
  
  
  CONCLUSIONS
  We found that frailty may independently predict the development of AKI and adverse outcomes in geriatric inpatients.
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea.
authors.forename: Seon Ha
authors.initials: SH
authors.lastname: Baek
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea.
authors.forename: Sung Woo
authors.initials: SW
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea.
authors.forename: Sun-Wook
authors.initials: SW
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea.
authors.forename: Shin Young
authors.initials: SY
authors.lastname: Ahn
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea.
authors.forename: Mi-Yeon
authors.initials: MY
authors.lastname: Yu
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea.
authors.forename: Kwang-Il
authors.initials: KI
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea.
authors.forename: Ho Jun
authors.initials: HJ
authors.lastname: Chin
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea.
authors.forename: Ki Young
authors.initials: KY
authors.lastname: Na
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea.
authors.forename: Dong-Wan
authors.initials: DW
authors.lastname: Chae
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea.
authors.forename: Sejoong
authors.initials: S
authors.lastname: Kim
mesh_terms: D058186:Acute Kidney Injury / Q000453:epidemiology* / Q000401:mortality; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D016330:Frail Elderly / Q000706:statistics & numerical data*; D015577:Geriatric Assessment / Q000379:methods*; D017052:Hospital Mortality; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D016017:Odds Ratio; D012189:Retrospective Studies; D012307:Risk Factors