title: Association of Performance-Based and Self-Reported Function-Based Definitions of Frailty with Mortality among Patients Receiving Hemodialysis.
abstract: OBJECTIVE
  Frailty is common among patients on dialysis and increases vulnerability to dependency and death.
  
  
  METHODS
  We examined the predictive ability of frailty on the basis of physical performance and self-reported function in participants of a US Renal Data System special study that enrolled a convenience sample of 771 prevalent patients on hemodialysis from 14 facilities in the Atlanta and northern California areas from 2009 to 2011. Performance-based frailty was assessed using direct measures of grip strength (weakness) and gait speed along with weight loss, exhaustion, and low physical activity; poor self-reported function was substituted for weakness and slow gait speed in the self-reported function-based definition. For both definitions, patients meeting three or more criteria were considered frail.
  
  
  RESULTS
  The mean age of 762 patients included in analyses was 57.1±14.2 years old; 240 patients (31%) met the physical performance-based definition of frailty, and 396 (52%) met the self-reported function-based definition. There were 106 deaths during 1.7 (interquartile range, 1.4-2.4) years of follow-up. After adjusting for demographic and clinical characteristics, the hazard ratio (HR) for mortality for the performance-based definition (2.16; 95% confidence interval [95% CI], 1.41 to 3.29) was slightly higher than that of the self-reported function-based definition (HR, 1.93; 95% CI, 1.24 to 3.00). Patients who met the self-report-based definition but not the physical performance definition of frailty (n=192) were not at statistically significantly higher risk of mortality than those who were not frail by either definition (n=330; HR, 1.41; 95% CI, 0.81 to 2.45), but those who met both definitions of frailty (n=204) were at significantly higher risk (HR, 2.46; 95% CI, 1.51 to 4.01).
  
  
  CONCLUSIONS
  Frailty, defined using either direct tests of physical performance or self-reported physical function, was associated with higher mortality among patients receiving hemodialysis. Future studies are needed to determine the utility of assessing frailty in clinical practice.
authors.affiliation: Division of Nephrology and Nephrology Section, San Francisco Veterans Affairs Medical Center, San Francisco, California; Department of Epidemiology and Biostatistics, University of California, San Francisco, California; Kirsten.johansen@ucsf.edu.
authors.forename: Kirsten L
authors.initials: KL
authors.lastname: Johansen
authors.affiliation: Division of Nephrology, University of California, Davis, California; and.
authors.forename: Lorien S
authors.initials: LS
authors.lastname: Dalrymple
authors.affiliation: Department of Epidemiology and Biostatistics, University of California, San Francisco, California;
authors.forename: David
authors.initials: D
authors.lastname: Glidden
authors.affiliation: Division of Nephrology and Nephrology Section, San Francisco Veterans Affairs Medical Center, San Francisco, California;
authors.forename: Cynthia
authors.initials: C
authors.lastname: Delgado
authors.affiliation: Division of Nephrology, University of California, Davis, California; and.
authors.forename: George A
authors.initials: GA
authors.lastname: Kaysen
authors.affiliation: Department of Epidemiology and Biostatistics, University of California, San Francisco, California;
authors.forename: Barbara
authors.initials: B
authors.lastname: Grimes
authors.affiliation: Division of Nephrology, Stanford University School of Medicine, Stanford, California.
authors.forename: Glenn M
authors.initials: GM
authors.lastname: Chertow
mesh_terms: D003430:Cross-Sectional Studies; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018908:Muscle Weakness; D016016:Proportional Hazards Models; D011597:Psychomotor Performance; D006435:Renal Dialysis / Q000401:mortality*; D057566:Self Report; D000072797:Walking Speed
keywords: ESRD; fatigue; follow-up studies; gait; geriatric nephrology; hand strength; health status indicators; hemodialysis; humans; physical fitness; survival