title: Diagnostic accuracy of spot urine protein-to-creatinine ratio for proteinuria and its association with adverse pregnancy outcomes in Chinese pregnant patients with pre-eclampsia.
abstract: BACKGROUND
  International guidelines have endorsed spot urine protein-to-creatinine ratio of >30 mg protein/mmol creatinine as an alternative to a 24-hour urine sample to represent significant proteinuria. This study aimed to determine the accuracy of spot urine protein-to-creatinine ratio in predicting significant proteinuria and adverse pregnancy outcome.
  
  
  METHODS
  This case series was conducted in a regional obstetric unit in Hong Kong. A total of 120 Chinese pregnant patients with pre-eclampsia delivered at Queen Elizabeth Hospital from January 2011 to December 2013 were included. Relationship of spot urine protein-to-creatinine ratio and 24-hour proteinuria; accuracy of the ratio against 24-hour urine protein at different cut-offs; and relationship of such ratio and adverse pregnancy outcome were studied.
  
  
  RESULTS
  Spot urine protein-to-creatinine ratio was correlated with 24-hour urine protein with Pearson correlation coefficient of 0.914 (P<0.0001) when the ratio was <200 mg/mmol. The optimal threshold of spot urine protein-to-creatinine ratio for diagnosing proteinuria in Chinese pregnant patients (33 mg/mmol) was similar to that stated in the international literature (30 mg/mmol). A cut-off of 20 mg/mmol provided a 100% sensitivity, and 52 mg/mmol provided a 100% specificity. There was no significant difference in spot urine protein-to-creatinine ratio between cases with and without adverse pregnancy outcome.
  
  
  CONCLUSIONS
  Spot urine protein-to-creatinine ratio had a positive and significant correlation with 24-hour urine results in Chinese pre-eclamptic women when the ratio was <200 mg/mmol. Nonetheless, this ratio was not predictive of adverse pregnancy outcome.
authors.affiliation: Department of Obstetrics and Gynaecology, Queen Elizabeth Hospital, Jordan, Hong Kong.
authors.forename: H C
authors.initials: HC
authors.lastname: Cheung
authors.affiliation: Department of Obstetrics and Gynaecology, Queen Elizabeth Hospital, Jordan, Hong Kong.
authors.forename: K Y
authors.initials: KY
authors.lastname: Leung
authors.affiliation: Department of Medicine, Queen Elizabeth Hospital, Jordan, Hong Kong.
authors.forename: C H
authors.initials: CH
authors.lastname: Choi
mesh_terms: D000293:Adolescent; D000328:Adult; D001794:Blood Pressure; D003404:Creatinine / Q000652:urine*; D005260:Female; D006723:Hong Kong; D006801:Humans; D008875:Middle Aged; D011225:Pre-Eclampsia / Q000209:etiology / Q000652:urine*; D011247:Pregnancy; D011248:Pregnancy Complications / Q000209:etiology / Q000652:urine*; D011256:Pregnancy Outcome; D011507:Proteinuria / Q000175:diagnosis*; D012372:ROC Curve; D012680:Sensitivity and Specificity; D016482:Urinalysis; D055815:Young Adult
chemical_list: D003404:Creatinine
keywords: Creatinine/urine; Proteinuria/diagnosis; Sensitivity and specificity