title: Cognitive function and all-cause mortality in maintenance hemodialysis patients.
abstract: BACKGROUND
  Cognitive impairment is common in hemodialysis patients and is associated with significant morbidity. Limited information exists about whether cognitive impairment is associated with survival and whether the type of cognitive impairment is important.
  
  
  METHODS
  Longitudinal cohort.
  
  
  METHODS
  Cognitive function was assessed at baseline and yearly using a comprehensive battery of cognitive tests in 292 prevalent hemodialysis patients.
  
  
  METHODS
  Using principal component analysis, individual test results were reduced into 2 domain scores, representing memory and executive function. By definition, each score carried a mean of 0 and SD of 1.
  
  
  RESULTS
  Association of each score with all-cause mortality was assessed using Cox proportional hazards models adjusted for demographics and dialysis and cardiovascular (CV) risk factors.
  
  
  RESULTS
  Mean age of participants was 63 years, 53% were men, 23% were African American, and 90% had at least a high school education. During a median follow-up of 2.1 (IQR, 1.1-3.7) years, 145 deaths occurred. Each 1-SD better executive function score was associated with a 35% lower hazard of mortality (HR, 0.65; 95% CI, 0.55-0.76). In models adjusting for demographics and dialysis-related factors, this relationship was partially attenuated but remained significant (HR, 0.81; 95% CI, 0.67-0.98), whereas adjustment for CV disease and heart failure resulted in further attenuation (HR, 0.87; 95% CI, 0.72-1.06). Use of time-dependent models showed a similar unadjusted association (HR, 0.62; 95% CI, 0.54-0.72), with the relationship remaining significant after adjustment for demographics and dialysis and CV risk factors (HR, 0.79; 95% CI, 0.66-0.94). Better memory was associated with lower mortality in univariate analysis (HR per 1 SD, 0.82; 95% CI, 0.69-0.96), but not when adjusting for demographics (HR, 1.00; 95% CI, 0.83-1.19).
  
  
  CONCLUSIONS
  Patients with dementia were excluded from the full battery, perhaps underestimating the strength of the association.
  
  
  CONCLUSIONS
  Worse executive function and memory are associated with increased risk of mortality. For memory, this association is explained by patient demographics, whereas for executive function, this relationship may be explained in part by CV disease burden.
authors.affiliation: Division of Nephrology, Department of Medicine, Tufts Medical Center, Boston, MA.
authors.forename: David A
authors.initials: DA
authors.lastname: Drew
authors.affiliation: Division of Nephrology, Department of Medicine, Tufts Medical Center, Boston, MA.
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Weiner
authors.affiliation: The Institute for Clinical Research and Health Policy Studies, Tufts Medical Center, Boston, MA; Tufts Clinical and Translational Science Institute, Tufts University, Boston, MA.
authors.forename: Hocine
authors.initials: H
authors.lastname: Tighiouart
authors.affiliation: Department of Psychiatry, Tufts Medical Center, Boston, MA.
authors.forename: Tammy
authors.initials: T
authors.lastname: Scott
authors.affiliation: Division of Nephrology, Department of Medicine, Tufts Medical Center, Boston, MA.
authors.forename: Kristina
authors.initials: K
authors.lastname: Lou
authors.affiliation: Division of Nephrology, Department of Medicine, Tufts Medical Center, Boston, MA.
authors.forename: Amy
authors.initials: A
authors.lastname: Kantor
authors.affiliation: Division of Nephrology, Department of Medicine, Tufts Medical Center, Boston, MA.
authors.forename: Li
authors.initials: L
authors.lastname: Fan
authors.affiliation: Saint Elizabeth's Medical Center, Boston, MA.
authors.forename: James A
authors.initials: JA
authors.lastname: Strom
authors.affiliation: Division of Nephrology, Brigham and Women's Hospital, Boston, MA.
authors.forename: Ajay K
authors.initials: AK
authors.lastname: Singh
authors.affiliation: Division of Nephrology, Department of Medicine, Tufts Medical Center, Boston, MA. Electronic address: msarnak@tuftsmedicalcenter.org.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Sarnak
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003072:Cognition Disorders / Q000175:diagnosis* / Q000401:mortality*; D015331:Cohort Studies; D056344:Executive Function / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008568:Memory / Q000502:physiology; D008875:Middle Aged; D009026:Mortality / Q000639:trends; D006435:Renal Dialysis / Q000401:mortality* / Q000639:trends
keywords: Cognition; cardiovascular disease; cognitive impairment; end-stage renal disease (ESRD); executive function; hemodialysis; memory; mortality; neurocognitive testing