title: Higher levels of cystatin C are associated with worse cognitive function in older adults with chronic kidney disease: the chronic renal insufficiency cohort cognitive study.
abstract: OBJECTIVE
  To determine the association between cognition and levels of cystatin C in persons with chronic kidney disease (CKD).
  
  
  METHODS
  Prospective observational study.
  
  
  METHODS
  Chronic Renal Insufficiency Cohort Cognitive Study.
  
  
  METHODS
  Individuals with a baseline cognitive assessment completed at the same visit as serum cystatin C measurement (N = 821; mean age 64.9, 50.6% male, 48.6% white).
  
  
  METHODS
  Levels of serum cystatin C were categorized into tertiles; cognitive function was assessed using six neuropsychological tests. Scores on these tests were compared across tertiles of cystatin C using linear regression and logistic regression to examine the association between cystatin C level and cognitive performance (1 standard deviation difference from the mean).
  
  
  RESULTS
  After multivariable adjustment for age, race, education, and medical comorbidities in linear models, higher levels of cystatin C were associated with worse cognition on the modified Mini-Mental State Examination, Buschke Delayed Recall, Trail-Making Test Part (Trails) A and Part B, and Boston Naming (P < .05 for all). This association remained statistically significant for Buschke Delayed Recall (P = .01) and Trails A (P = .03) after additional adjustment for estimated glomerular filtration rate (eGFR). The highest tertile of cystatin C was associated with greater likelihood of poor performance on Trails A (odds ratio (OR) = 2.17, 95% confidence interval (CI) = 1.16-4.06), Trails B (OR = 1.89, 95% CI = 1.09-3.27), and Boston Naming (OR = 1.85, 95% CI = 1.07-3.19) than the lowest tertile after multivariate adjustment in logistic models.
  
  
  CONCLUSIONS
  In individuals with CKD, higher serum cystatin C levels were associated with worse cognition and greater likelihood of poor cognitive performance on attention, executive function, and naming. Cystatin C is a marker of cognitive impairment and may be associated with cognition independent of eGFR.
authors.affiliation: Department of Psychiatry, School of Medicine, University of California at San Francisco, San Francisco, California; Department of Neurology, School of Medicine, University of California at San Francisco, San Francisco, California; Department of Epidemiology and Biostatistics, School of Medicine, University of California at San Francisco, San Francisco, California; San Francisco Veterans Affairs Medical Center, San Francisco, California.
authors.forename: Kristine
authors.initials: K
authors.lastname: Yaffe
authors.forename: Manjula
authors.initials: M
authors.lastname: Kurella-Tamura
authors.forename: Lynn
authors.initials: L
authors.lastname: Ackerson
authors.forename: Tina D
authors.initials: TD
authors.lastname: Hoang
authors.forename: Amanda H
authors.initials: AH
authors.lastname: Anderson
authors.forename: Mark
authors.initials: M
authors.lastname: Duckworth
authors.forename: Alan S
authors.initials: AS
authors.lastname: Go
authors.forename: Marie
authors.initials: M
authors.lastname: Krousel-Wood
authors.forename: John W
authors.initials: JW
authors.lastname: Kusek
authors.forename: James P
authors.initials: JP
authors.lastname: Lash
authors.forename: Akinlolu
authors.initials: A
authors.lastname: Ojo
authors.forename: Nancy
authors.initials: N
authors.lastname: Robinson
authors.forename: Ashwini R
authors.initials: AR
authors.lastname: Sehgal
authors.forename: James H
authors.initials: JH
authors.lastname: Sondheimer
authors.forename: Susan
authors.initials: S
authors.lastname: Steigerwalt
authors.forename: Raymond R
authors.initials: RR
authors.lastname: Townsend
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D003072:Cognition Disorders / Q000097:blood* / Q000175:diagnosis; D055316:Cystatin C / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009483:Neuropsychological Tests; D011446:Prospective Studies; D051436:Renal Insufficiency, Chronic / Q000453:epidemiology*; D014481:United States / Q000453:epidemiology
chemical_list: D015415:Biomarkers; D055316:Cystatin C
keywords: chronic kidney disease; cognition; cystatin C