title: Mortality risk stratification in chronic kidney disease: one size for all ages?
abstract: Current National Kidney Foundation Kidney Disease Outcomes Quality Initiative staging criteria for chronic kidney disease (CKD) are intended to apply to all age groups. However, it is unclear whether different levels of estimated GFR (eGFR) have the same prognostic significance in older and younger patients. The study cohort was composed of Department of Veterans Affairs (VA) patients who were aged 18 to 100 yr and had at least one outpatient serum creatinine measurement between October 1, 2001, and September 30, 2002 (n=2583,911). Patients with ESRD were excluded. GFR was estimated using the Modification of Diet in Renal Disease equation using each patient's first outpatient creatinine measurement during the study period. The association of eGFR with survival was measured by age group. Twenty percent of cohort patients had an eGFR<60 ml/min per 1.73 m2, ranging from 3% among 18- to 44-yr-olds to as high as 49% among 85- to 100-yr-olds. Fifty-two percent (n=266,421) of cohort patients with an eGFR<60 ml/min per 1.73 m2 had "very" moderate reductions in eGFR into the 50- to 59-ml/min per 1.73 m2 range. The association of eGFR with mortality was weaker in the elderly than in younger age groups: Whereas severe reductions in eGFR were associated with an increased risk for death in all age groups, "very" moderate reductions in eGFR (50 to 59 ml/min per 1.73 m2) were associated with an increased adjusted risk for death only among patients who were younger than 65 yr. Age-related attenuation of the association of eGFR with mortality was also present among women and black patients. In the clinical setting, mortality risk stratification in elderly patients should not be based on the same eGFR cut points as for younger age groups and would benefit from finer categorization of the 30- to 59-ml/min per 1.73 m2 eGFR group.
authors.affiliation: Department of Medicine, University of California San Francisco, VA Medical Center, San Francisco, 111J Nephrology, 4150 Clement Street, San Francisco, CA 94121, USA. ann.o'hare@med.va.gov
authors.forename: Ann M
authors.initials: AM
authors.lastname: O'Hare
authors.forename: Daniel
authors.initials: D
authors.lastname: Bertenthal
authors.forename: Kenneth E
authors.initials: KE
authors.lastname: Covinsky
authors.forename: C Seth
authors.initials: CS
authors.lastname: Landefeld
authors.forename: Saunak
authors.initials: S
authors.lastname: Sen
authors.forename: Kala
authors.initials: K
authors.lastname: Mehta
authors.forename: Michael A
authors.initials: MA
authors.lastname: Steinman
authors.forename: Ann
authors.initials: A
authors.lastname: Borzecki
authors.forename: Louise C
authors.initials: LC
authors.lastname: Walter
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002423:Cause of Death; D015331:Cohort Studies; D018450:Disease Progression; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007676:Kidney Failure, Chronic / Q000175:diagnosis / Q000401:mortality* / Q000628:therapy*; D007677:Kidney Function Tests; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012016:Reference Values; D018570:Risk Assessment; D012720:Severity of Illness Index; D016019:Survival Analysis; D014481:United States / Q000453:epidemiology