title: [Employing age-related cut-off values results in fewer patients with renal impairment in secondary care].
abstract: OBJECTIVE
  To describe the consequences on the burden for primary and secondary care in the Netherlands, of using age-related cut-off values for renal function which follow the Dutch national transmural agreement (LTA) for 'Chronic renal impairment', rather than the 'Kidney disease outcome quality initiative' (K/DOQI) guidelines.
  
  
  METHODS
  Observational cross-sectional study.
  
  
  METHODS
  82,424 patients whose serum creatinine had been determined in 2009 were identified from the laboratory registry of the Isala Clinics in Zwolle, the Netherlands. The glomerular filtration rate was estimated using the abbreviated Modification of Diet in Renal Disease (MDRD) equation (eGFR). Burden of care was defined as the necessity for referral or consultation in secondary care. The number of people that would have been referred using the K/DOQI guideline that refers all those with an eGFR < 60 ml/min/1.73 m², was compared to a situation using age-related cut-off values in the referral policy.
  
  
  RESULTS
  The study population contained 82,424 people; 45.3% were men; age range was 19-106 years; 38.7% were > 65 years. 19% of the population (n = 15,637) had an eGFR < 60 ml/min/1.73 m2 and would have been referred had the K/DOQI guidelines been applied; 11,935 of those 15,637 were > 65 years. The use of the LTA for 'Chronic renal impairment', that includes age as one of the criteria, would have resulted in the referral of 3,303/15,637 patients (2,011 of those 3,303 were > 65 years), and resulted in consultation with a nephrologist for 5,748/15,637 patients (3,338/5,748 were > 65 years). The majority of patients aged > 65 years and with an eGFR < 60 ml/min/1.73 m2 (55%) could be treated in primary care without consultation of secondary care or referral.
  
  
  CONCLUSIONS
  The categorization applied by the current LTA for 'Chronic renal impairment', whereby age-related cut-off values are used in the referral policy, will result in more targeted referral to secondary care, especially in the elderly patient group, when compared to application of the K/DOQI guidelines.
authors.affiliation: Isala Klinieken, Zwolle, Diabetes Kenniscentrum, the Netherlands. i.drion@isala.nl
authors.forename: Iefke
authors.initials: I
authors.lastname: Drion
authors.forename: Hanneke
authors.initials: H
authors.lastname: Joosten
authors.forename: Kornelis J J
authors.initials: KJ
authors.lastname: van Hateren
authors.forename: Nanne
authors.initials: N
authors.lastname: Kleefstra
authors.forename: Johannes G
authors.initials: JG
authors.lastname: Krabbe
authors.forename: Jack F M
authors.initials: JF
authors.lastname: Wetzels
authors.forename: Henk J G
authors.initials: HJ
authors.lastname: Bilo
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D003404:Creatinine / Q000097:blood; D003430:Cross-Sectional Studies; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007676:Kidney Failure, Chronic / Q000145:classification* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D017410:Practice Guidelines as Topic; D012015:Reference Standards; D012017:Referral and Consultation; D055815:Young Adult
chemical_list: D003404:Creatinine