Research

Diagnostic accuracy of urinary spot protein:creatinine ratio for proteinuria in hypertensive pregnant women: systematic review

BMJ 2008; 336 doi: 10.1136/bmj.39532.543947.BE (Published 1 May 2008)
Cite this as: BMJ 2008;336:1003
  1. Anne-Marie Côté, obstetric medicine fellow1,
  2. Mark A Brown, professor of medicine2,
  3. Elaine Lam, medical student1,
  4. Peter von Dadelszen, associate professor of obstetrics and gynaecology3,
  5. Tabassum Firoz, resident internal medicine1,
  6. Robert M Liston, professor and chair in obstetrics and gynaecology3,
  7. Laura A Magee, clinical associate professor of medicine3
  1. 1BC Women’s Hospital and Health Centre, Vancouver, BC, Canada
  2. 2St George Hospital and University of New South Wales, Kogarah, Sydney, NSW, Australia
  3. 3Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada V6H 3N1
  1. Correspondence to: L A Magee, BC Women’s Hospital and Health Centre, Vancouver, BC, Canada V6P 1S8 LMagee{at}cw.bc.ca
  • Accepted 12 March 2008

Abstract

Objective To review the spot protein:creatinine ratio and albumin:creatinine ratio as diagnostic tests for significant proteinuria in hypertensive pregnant women.

Design Systematic review.

Data sources Medline and Embase, the Cochrane Library, reference lists, and experts.

Review methods Literature search (1980-2007) for articles of the spot protein:creatinine ratio or albumin:creatinine ratio in hypertensive pregnancy, with 24 hour proteinuria as the comparator.

Results 13 studies concerned the spot protein:creatinine ratio (1214 women with primarily gestational hypertension). Nine studies reported sensitivity and specificity for eight cut-off points, median 24 mg/mmol (range 17-57 mg/mmol; 0.15-0.50 mg/mg). Laboratory assays were not well described. Diagnostic test characteristics were recalculated for a cut-off point of 30 mg/mmol. No significant heterogeneity in cut-off points was found between studies over a range of proteinuria. Pooled values gave a sensitivity of 83.6% (95% confidence interval 77.5% to 89.7%), specificity of 76.3% (72.6% to 80.0%), positive likelihood ratio of 3.53 (2.83 to 4.49), and negative likelihood ratio of 0.21 (0.13 to 0.31) (nine studies, 1003 women). Two studies of the spot albumin:creatinine ratio (225 women) found optimal cut-off points of 2 mg/mmol for proteinuria of 0.3 g/day or more and 27 mg/mmol for albuminuria.

Conclusion The spot protein:creatinine ratio is a reasonable “rule-out” test for detecting proteinuria of 0.3 g/day or more in hypertensive pregnancy. Information on use of the albumin:creatinine ratio in these women is insufficient.

Footnotes

  • We thank Ruth Milner and Victor Espinosa for statistical advice, Samantha Reineking for help with the literature search, Catherine Halstead for providing information on laboratory methods, and the following authors for additional information about their own studies: M Brown, A B Neithardt, H Nisell, J G Ramos, T L Wheeler, and W Yamasmit.

  • Contributors: AMC, ELM, and LAM extracted the data. AMC, PvD, and LAM analysed and presented the data. AMC, MAB, PvD, RML, and LAM drafted and edited the manuscript. AMC and LAM are guarantors.

  • Funding: At the time of the work, AMC was an obstetric medicine fellow funded by the Centre de Recherche Médicale de l’Université de Sherbrooke. LAM has a scholar award from the Michael Smith Foundation for Health Research and an establishment grant from the Child and Family Research Institute of British Columbia. PvD is a new investigator for the Child and Family Research Institute and a senior scholar at the Michael Smith Foundation for Health Research, and has an establishment grant from the Child and Family Research Institute, from which PvD also receives an investigatorship.

  • Competing interest: None declared.

  • Ethical approval: not required for this diagnostic meta-analysis of published studies.

  • Provenance and peer review: Not commissioned; externally peer reviewed.

  • Accepted 12 March 2008

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