title: Clinical utility of spot urine protein-to-creatinine ratio modified by estimated daily creatinine excretion in children.
abstract: The spot urine protein-to-creatinine ratio (UPCR) is widely used to predict 24-h urine protein (24-h UP) excretion. In patients with low daily urine creatinine excretion (UCr), however, the UPCR may overestimate 24-h UP. The aim of this study was to predict 24-h UP using UPCR adjusted by estimated 24-h UCr in children.
  
  
  
  This study included 442 children whose 24-h UP and spot UPCR were measured concomitantly. Estimated 24-h UCr was calculated using three previously existing equations. We estimated the 24-h UP excretion from UPCR by multiplying the estimated UCr. The results were compared with the measured 24-h UP.
  
  
  
  There was a strong correlation between UPCR and 24-h UP (r = 0.801, P < 0.001), and the correlation improved after multiplying the UPCR by the measured UCr (r = 0.847, P < 0.001). Using the estimated UCr rather than the measured UCr, there was high accuracy and strong correlation between the estimated UPCR weighted by the Cockcroft-Gault equation and 24-h UP. Improvement was also observed in the subgroup (proteinuria vs. non-proteinuria) analysis, particularly in the proteinuria group.
  
  
  
  The spot UPCR multiplied by the estimated UCr improved the accuracy of prediction of the 24-h UP in children.
authors.affiliation: Department of Pediatrics, Chonnam National University Medical School, 42 Jebong-ro, Dong-gu, Gwangju, 61469, Republic of Korea.
authors.forename: Eun Mi
authors.initials: EM
authors.lastname: Yang
authors.affiliation: Department of Pediatrics, Chonnam National University Medical School, 42 Jebong-ro, Dong-gu, Gwangju, 61469, Republic of Korea.
authors.forename: Bo Ae
authors.initials: BA
authors.lastname: Yoon
authors.affiliation: Department of Internal Medicine, Chonnam National University Medical School, 42 Jebong-ro, Dong-gu, Gwangju, 61469, Republic of Korea.
authors.forename: Soo Wan
authors.initials: SW
authors.lastname: Kim
authors.affiliation: Department of Pediatrics, Chonnam National University Medical School, 42 Jebong-ro, Dong-gu, Gwangju, 61469, Republic of Korea. cjkim@jnu.ac.kr.
authors.forename: Chan Jong
authors.identifier: 0000-0001-6519-2427
authors.initials: CJ
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003404:Creatinine / Q000378:metabolism / Q000652:urine*; D005260:Female; D006801:Humans; D007223:Infant; D007677:Kidney Function Tests / Q000379:methods*; D008297:Male; D011507:Proteinuria / Q000378:metabolism / Q000652:urine*; D065667:Renal Elimination; D012189:Retrospective Studies
chemical_list: D003404:Creatinine
keywords: 24-hour urine protein; Children; Creatinine excretion rate; Proteinuria; Spot urine protein-to-creatinine ratio