title: The clinical utility of serum uric acid measurements in hypertensive diseases of pregnancy.
abstract: OBJECTIVE
  Our purpose was to evaluate the clinical utility of serum uric acid measurements in the hypertensive diseases of pregnancy.
  
  
  METHODS
  We performed a nested case-control study to assess the clinical utility of serum uric acid measurements in women with hypertensive diseases of pregnancy. We identified 344 women who had serum uric acid measurements at term and categorized them into five diagnostic groups according to definitions of hypertensive diseases in pregnancy published by the National Working Group on Hypertension in Pregnancy: transient hypertension of pregnancy (n = 69), preeclampsia (n = 130), chronic hypertension (n = 23), chronic hypertension with superimposed preeclampsia (n = 29), and normal (n = 93). We compared the mean uric acid concentration for each group with use of a one-way analysis of variance and Scheffe's post hoc test and calculated the sensitivities and specificities in diagnosing preeclampsia as well as the likelihood ratios for serum uric acid values of 5.5, 6.0, and 6.5 mg/dl. We also examined the correlation between serum uric acid levels and several clinical outcome measures in women with hypertensive diseases of pregnancy.
  
  
  RESULTS
  The mean serum uric acid values for women with preeclampsia (6.2 +/- 1.4 mg/dl) and transient hypertension (5.6 +/- 1.7 mg/dl) were significantly higher than those of controls (4.3 +/- 0.8 mg/dl, p < 0.05). The difference in mean serum uric acid values between women with chronic hypertension (4.9 +/- 1.0 mg/dl) and superimposed preeclampsia (5.8 +/- 1.4 mg/dl) were not statistically significant. The likelihood ratio of having preeclampsia with a serum uric acid value of 5.5 mg/dl was 1.41 in gestational hypertension of pregnancy and 2.5 in chronic hypertension. With use of a receiver-operator characteristic curve, we were unable to identify a serum uric acid value that could be used to differentiate various hypertensive diseases of pregnancy. There was a weak correlation between serum uric acid values and several clinical outcome measures of preeclampsia (r = 0.06 to 0.26).
  
  
  CONCLUSIONS
  Although mean serum uric acid values are elevated in women with preeclampsia, the clinical utility of serum uric acid values in differentiating various hypertensive diseases of pregnancy appears to be limited. In the setting of chronic hypertension, however, a serum uric acid level of > or = 5.5 mg/dl could identify women with an increased likelihood of having superimposed preeclampsia.
authors.affiliation: Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco, USA.
authors.forename: K H
authors.initials: KH
authors.lastname: Lim
authors.forename: S A
authors.initials: SA
authors.lastname: Friedman
authors.forename: J L
authors.initials: JL
authors.lastname: Ecker
authors.forename: L
authors.initials: L
authors.lastname: Kao
authors.forename: S J
authors.initials: SJ
authors.lastname: Kilpatrick
mesh_terms: D016022:Case-Control Studies; D002908:Chronic Disease; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000175:diagnosis*; D011225:Pre-Eclampsia / Q000097:blood / Q000175:diagnosis; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular / Q000097:blood / Q000175:diagnosis*; D012372:ROC Curve; D012016:Reference Values; D012680:Sensitivity and Specificity; D014527:Uric Acid / Q000097:blood*
chemical_list: D014527:Uric Acid