title: Urine Albumin-Creatinine Ratio Versus Albumin Excretion for Albuminuria Staging: A Prospective Longitudinal Cohort Study.
abstract: BACKGROUND
  New guidelines advocate the use of albumin-creatinine ratio (ACR) in a urine sample instead of 24-hour urinary albumin excretion (UAE) for staging albuminuria. Concern has been expressed that this may result in misclassification for reasons including interindividual differences in urinary creatinine excretion.
  
  
  METHODS
  Prospective longitudinal cohort study.
  
  
  METHODS
  We examined 7,623 participants of the PREVEND and RENAAL studies for reclassified when using ACR instead of 24-hour UAE, the characteristics of reclassified participants, and their outcomes. Albuminuria was categorized into 3 ACR and UAE categories: <30, 30 to 300, and >300mg/g or mg/24 h, respectively.
  
  
  METHODS
  Baseline ACR and 24-hour UAE.
  
  
  RESULTS
  Cardiovascular (CV) morbidity and mortality and all-cause mortality.
  
  
  RESULTS
  When using ACR in the early morning void instead of 24-hour UAE, 88% of participants were classified in corresponding albuminuria categories. 307 (4.0%) participants were reclassified to a higher, and 603 (7.9%), to a lower category. Participants who were reclassified to a higher ACR category in general had a worse CV risk profile compared with nonreclassified participants, whereas the reverse was true for participants reclassified to a lower ACR category. Similarly, Cox proportional hazards regression analyses showed that reclassification to a higher ACR category was associated with a tendency for increased risk for CV morbidity and mortality and all-cause mortality, whereas reclassification to a lower ACR category was associated with a tendency for lower risk. Net reclassification improvement, adjusted for age, sex, and duration of follow-up, was 0.107 (P=0.002) for CV events and 0.089 (P<0.001) for all-cause mortality.
  
  
  CONCLUSIONS
  Early morning void urine collection instead of spot urine collection.
  
  
  CONCLUSIONS
  Our results indicate that there is high agreement between early morning void ACR and 24-hour UAE categories. Reclassification is therefore limited, but when present, is generally indicative of the presence of CV risk factors and prognosis.
authors.affiliation: Department of Health Sciences, Community and Occupational Medicine, Groningen, the Netherlands.
authors.forename: Priya
authors.initials: P
authors.lastname: Vart
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Groningen, the Netherlands.
authors.forename: Lieneke
authors.initials: L
authors.lastname: Scheven
authors.affiliation: Department of Clinical Pharmacology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands.
authors.forename: Hiddo J
authors.initials: HJ
authors.lastname: Lambers Heerspink
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Groningen, the Netherlands.
authors.forename: Paul E
authors.initials: PE
authors.lastname: de Jong
authors.affiliation: Department of Clinical Pharmacology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands.
authors.forename: Dick
authors.initials: D
authors.lastname: de Zeeuw
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Groningen, the Netherlands. Electronic address: r.t.gansevoort@umcg.nl.
authors.forename: Ron T
authors.initials: RT
authors.lastname: Gansevoort
mesh_terms: D000419:Albuminuria / Q000175:diagnosis / Q000652:urine*; D015331:Cohort Studies; D003404:Creatinine / Q000652:urine*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012720:Severity of Illness Index; D016482:Urinalysis
chemical_list: D003404:Creatinine
keywords: Albuminuria; PREVEND (Prevention of Renal and Vascular Endstage Disease); RENAAL (Reduction of Endpoints in Non−Insulin-Dependent Diabetes With the Angiotensin II Antagonist Losartan); albumin-creatinine ratio (ACR); albuminuria staging; cardiovascular outcome; mortality; risk categorization; urinary albumin excretion (UAE)