title: [Laboratory manifestations associated with chronic renal failure: what degree of estimated glomerular filtration can be used for its detection in the elderly?].
abstract: OBJECTIVE
  A classification of chronic kidney disease (CKD) based on stages of glomerular filtration (GF) has recently been developed. Thus, chronic renal failure (CRF) is based on GF <60 ml/min. Our goal was to study the presence of typical manifestations of CRF in elderly individuals with a GF of <60 ml/min (stage 3-5) and to determine the cut-off value at which GF can be used to detect these manifestations.
  
  
  METHODS
  We performed a cross-sectional study in clinically-stable elderly patients attending the geriatrics and nephrology outpatient department. The estimated GF (GFe) was established with the Cockroft-Gault and abbreviated Modification of Diet in Renal Disease Study (MDRD) formulae. Because these patients had a GF of less than 60 ml/min, they were expected to show the manifestations associated with CRF (anaemia, metabolic acidosis, abnormal bone and mineral metabolism). We evaluated the occurrence of these manifestations and the GF cut-off at which they were detected. To do this, the population was divided into two groups: group A: patients with GFe > or = 30 ml/min (stage 3, N=48); and group B: patients with GFe <30 ml/min (stages 4-5, N=8).
  
  
  RESULTS
  Seventy percent of the patients had a GFe (MDRD) <60 ml/min (stage 3-5). Despite reduced GF, these patients did not show the typical manifestations of CRF. Group B showed higher plasmatic levels of creatinine, urea, uric acid, and potassium and required treatment with erythropoietin and calcium salts.
  
  
  CONCLUSIONS
  Many elderly people diagnosed with CKD with the current classification do not show manifestations of CRF. Estimation of the GF in elders should be generalized to correctly adjust medication to renal impairment rather than to classify elders into CKD stage.
authors.affiliation: Servicio de Nefrología, Hospital General de Segovia, Segovia, España. mheras@hgse.sacyl.es
authors.forename: Manuel
authors.initials: M
authors.lastname: Heras
authors.forename: María Teresa
authors.initials: MT
authors.lastname: Guerrero
authors.forename: María José
authors.initials: MJ
authors.lastname: Fernández-Reyes
authors.forename: Rosa
authors.initials: R
authors.lastname: Sánchez
authors.forename: Angélica
authors.initials: A
authors.lastname: Muñoz
authors.forename: María Cruz
authors.initials: MC
authors.lastname: Macias
authors.forename: Alvaro
authors.initials: A
authors.lastname: Molina
authors.forename: Florentino
authors.initials: F
authors.lastname: Prado
authors.forename: Fernando
authors.initials: F
authors.lastname: Alvarez-Ude
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007676:Kidney Failure, Chronic / Q000175:diagnosis* / Q000378:metabolism / Q000503:physiopathology; D008297:Male