title: Kidney function and prevalent and incident frailty.
abstract: OBJECTIVE
  Kidney disease is associated with physiologic changes that may predispose to frailty. This study sought to investigate whether lower levels of kidney function were associated with prevalent or incident frailty in Cardiovascular Health Study (CHS) participants.
  
  
  METHODS
  CHS enrolled community-dwelling adults age ≥65 years between 1989-1990 and 1992-1993. To examine prevalent frailty, included were 4150 participants without stroke, Parkinson disease, prescribed medications for Alzheimer disease or depression, or severely impaired cognition. To examine incident frailty, included were a subset of 3459 participants without baseline frailty or development of exclusion criteria during follow-up. The primary predictor was estimated GFR (eGFR) calculated using serum cystatin C (eGFR(cys)). Secondary analyses examined eGFR using serum creatinine (eGFR(SCr)). Outcomes were prevalent frailty and incident frailty at 4 years of follow-up. Frailty was ascertained on the basis of weight loss, exhaustion, weakness, slowness, and low physical activity.
  
  
  RESULTS
  The mean age was 75 years and the median eGFR(cys) was 73 ml/min per 1.73 m(2). Among participants with an eGFR(cys) <45 ml/min per 1.73 m(2), 24% had prevalent frailty. In multivariable analysis and compared with eGFR(cys) ≥90 ml/min per 1.73 m(2), eGFR(cys) categories of 45-59 (odds ratio [OR], 1.80; 95% confidence interval [CI], 1.17 to 2.75) and 15-44 (OR, 2.87; 95% CI, 1.72 to 4.77) were associated with higher odds of frailty, whereas 60-75 (OR, 1.14; 95% CI, 0.76 to 1.70) was not. In multivariable analysis, eGFR(cys) categories of 60-75 (incidence rate ratio [IRR], 1.72; 95% CI, 1.07 to 2.75) and 15-44 (IRR, 2.28; 95% CI, 1.23 to 4.22) were associated with higher incidence of frailty whereas 45-59 (IRR, 1.53; 95% CI, 0.90 to 2.60) was not. Lower levels of eGFR(SCr) were not associated with higher risk of prevalent or incident frailty.
  
  
  CONCLUSIONS
  In community-dwelling elders, lower eGFR(cys) was associated with a higher risk of prevalent and incident frailty whereas lower eGFR(SCr) was not. These findings highlight the importance of considering non-GFR determinants of kidney function.
authors.affiliation: Due to the number of contributing authors, the affiliations are provided in the Supplemental Material.
authors.forename: Lorien S
authors.initials: LS
authors.lastname: Dalrymple
authors.forename: Ronit
authors.initials: R
authors.lastname: Katz
authors.forename: Dena E
authors.initials: DE
authors.lastname: Rifkin
authors.forename: David
authors.initials: D
authors.lastname: Siscovick
authors.forename: Anne B
authors.initials: AB
authors.lastname: Newman
authors.forename: Linda F
authors.initials: LF
authors.lastname: Fried
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Sarnak
authors.forename: Michelle C
authors.initials: MC
authors.lastname: Odden
authors.forename: Michael G
authors.initials: MG
authors.lastname: Shlipak
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D015415:Biomarkers / Q000097:blood; D003404:Creatinine / Q000097:blood; D003430:Cross-Sectional Studies; D055316:Cystatin C / Q000097:blood; D005221:Fatigue / Q000453:epidemiology; D005260:Female; D016330:Frail Elderly; D015577:Geriatric Assessment; D005919:Glomerular Filtration Rate; D006801:Humans; D015994:Incidence; D057187:Independent Living; D007668:Kidney / Q000503:physiopathology*; D007674:Kidney Diseases / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology*; D016015:Logistic Models; D008297:Male; D009043:Motor Activity; D015999:Multivariate Analysis; D018908:Muscle Weakness / Q000453:epidemiology; D016017:Odds Ratio; D010641:Phenotype; D015995:Prevalence; D011446:Prospective Studies; D012307:Risk Factors; D013997:Time Factors; D014481:United States / Q000453:epidemiology; D015431:Weight Loss
chemical_list: D015415:Biomarkers; C525030:CST3 protein, human; D055316:Cystatin C; D003404:Creatinine