Oya DEMİRCİ, Pınar KUMRU, Arzu ARINKAN, Bülent TANDOĞAN, Habibe AYVACI, Resul ARISOY, Cem ARDIÇ, Ahmet S. TUĞRUL, Elif TOZKIR

Spot protein/creatinine ratio in preeclampsia as an alternative for 24-hour urine protein

Background: Proteinuria is a major component of preeclampsia. Urine protein measurement after 24-hour urine collection is the traditional standard method for the detection of proteinuria. It is timeconsuming. As an alternative, random spot sampling for a urine protein to creatinine (P/C) ratio has been investigated. Aims: The aim of the study was to determine the diagnostic accuracy of the protein to creatinine ratio (P/C) compared with 24-hour urine collection for the detection of remarkable proteinuria and to evaluate the P/C ratio for different proteinuria ranges in patients with preeclampsia. Study Design: Case-control study. Methods: Two hundred and eleven pregnant women who met the criteria of preeclampsia comprised the study group and fifty three pregnant women were taken as the control group. Spot urine specimens for measuring P/C ratio were obtained taken immediately before 24-hour urine collection. The correlation between the P/C ratio in the spot urine samples and urinary protein excretion in the 24-hour collections was examined using the Spearman correlation test. Results: It was found a good positive correlation between the P/C ratio and 24-hour protein excretion, with a correlation coefficient (r) of 0.758. The best cut-off which gave the maximum area under the curve was 0.45 for 300 mg, 0.9 for 1000 mg, 1.16 for 2000 mg, 1.49 for 3000 mg, 2.28 for 4000 mg and 2.63 for 5000 mg per 24h. A P/C ratio above 0.9 strongly predicts significant proteinuria for more than 1 gram (AUC 0.97, 95% CI: 0.94-0.99 and sensitivity, specificity, positive and negative predictive value of 91%, 95.4%, 95.2%, and 91.2%, respectively). Conclusion: The P/C ratio can be used as a screening test as a good predictor for remarkable proteinuria. The P/C ratio seems to be highly predictive for diagnosis to detect proteinuria over one gram and it could be used as a rapid alternative test in preeclamptic patients not to delay implementation treatment.

PDF

___

1.World Health Organization International Collaborative Study of Hypertensive Disorders of Pregnancy. Geographic variation in the incidence of hypertension in pregnancy. Am J Obstet Gyne- col 1988;158:80-3. [CrossRef]
2.Sibai BM, Gordon T, Thom E, Caritis SN, Klebanoff M, Mc- Nellis D, Paul RH. Risk factors for preeclampsia in healthy nulliparous women: a prospective multicenter study. The Na- tional Institute of Child Health and Human Development Net- work of Maternal-Fetal Medicine Units. Am J Obstet Gynecol 1995;172:642-8. [CrossRef]
3.Diagnosis and Management of Preeclampsia and Eclampsia. ACOG Practice Bulletin #33 2002.
4.Keane WF, Eknoyan G. Proteinuria, albuminuria, risk, assessment, detection, elimination (PARADE): a position paper of the National Kidney Foundation. Am J Kidney Dis 1999;33:1004-10. [CrossRef]
5.Boyd J, Newall R, Price C. Use of protein:creatinine ratio mea- surements on random urine samples for prediction of significant proteinuria: a systematic review. Clin Chem 2005;51:1577-1586. [CrossRef]
6.Wheeler TL 2nd, Blackhurst DW, Dellinger EH, Ramsey PS. Us- age of spot urine protein to creatinine ratios in the evaluation of preeclampsia. Am J Obstet Gynecol 2007;196:465.e1-4.
7.Rizk DE, Agarwal MM, Pathan JY, Obineche EN. Predicting proteinuria in hypertensive pregnancies with urinary protein- creatinine or calcium-creatinine ratio. J Perinatol 2007;27:272-7. [CrossRef]
8.Shahbazian N, Hosseini-Asl F. A comparison of spot urine protein-creatinine ratio with 24-hour urine protein excretion in women with preeclampsia. Iran J Kidney Dis 2008;2:127-31.
9. Robert M, Sepandj F, Liston RM, Dooley KC. Random protein- creatinine ratio for the quantitation of proteinuria in pregnancy. Obstet Gynecol 1997;90:893. [CrossRef]
10. Neithardt AB, Dooley SL, Borensztajn J. Prediction of 24-hour pro- tein excretion in pregnancy with a single voided urine protein-to- creatinine ratio. Am J Obstet Gynecol 2002;186:883. [CrossRef]
11. Eslamian L, Behnam F, Tehrani ZF, Jamal A, Marsoosi V. Ran- dom urine protein creatinine ratio as a preadmission test in hypertensive pregnancies with urinary protein creatinine ratio. Acta Med Iran 2011;49:81-4.
12. Durnwald C, Mercer B. A prospective comparison of total pro- tein/creatinine ratio versus24-hour urine protein in women with suspected preeclampsia. Am J Obstet Gynecol 2003;189:848-52. [CrossRef]
13. Haas DM, Sabi F, McNamara M, Rivera-Alsina M. Comparing ambulatory spot urine protein/creatinine ratios and 24-h urine protein measurements in normal pregnancies. J Matern Fetal Neonatal Med 2003;14:233-6. [CrossRef]
14. Al RA, Baykal C, Karacay O, Geyik PO, Altun S, Dolen I. Random urine protein-creatinine ratio to predict proteinuria in new-onset mild hypertension in late pregnancy. Obstet Gynecol 2004;104:367-71. [CrossRef]
15. Eknoyan G, Hostetter T, Bakris GL. Proteinuria and other mark- ers of chronic kidney disease: a position statement of the na- tional kidney foundation (NKF) and the national institute of dia- betes and digestive and kidney diseases (NIDDK). Am J Kidney Dis 2003;42:617. [CrossRef]
16. Morales JV, Weber R, Wagner MB, Barros EJ. Is morning uri- nary protein/creatinine ratio a reliable estimator of 24-hour pro- teinuria in patients with glomerulonephritis and different levels of renal function? J Nephrol 2004;17:666-72.
17. Morris RK, Riley RD, Doug M, Deeks JJ, Kilby MD. Diagnos- tic accuracy of spot urinary protein and albumin to creatinine ra- tios for detection of significant proteinuria or adverse pregnancy outcome in patients with suspected pre-eclampsia: systematic review and meta-analysis. BMJ 2012;345:e4342. [CrossRef]
18. Methven S, Traynor JP, Hair MD, St J OReilly D, Deighan CJ, MacGregor MS. Stratifying risk in chronic kidney disease: an observational study of UK guidelines for measuring total pro- teinuria and albuminuria. QJM 2011;104:663-70. [CrossRef]
19. Antunes VV, Veronese FJ, Morales JV. Diagnostic accuracy of the protein/creatinine ratio in urine samples to estimate 24-h pro- teinuria in patients with primary glomerulopathies: a longitudinal study. Nephrol Dial Transplant 2008;23:2242-6. [CrossRef]
20. Guy M, Borzomato JK, Newall RG, Kalra PA, Price CP. Protein and albumin-to-creatinine ratios in random urines accurately predict 24 h protein and albumin loss in patients with kidney disease. Ann Clin Biochem 2009;46:468-76. [CrossRef]