Comparison of methods to identify significant proteinuria in pregnancy in the outpatient setting PM

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Comparison of methods to identify significant
proteinuria in pregnancy in the outpatient
settingPM Kyle, JN Fielder, B Pullar, LJ
Horwood, PM MooreBJOG 2008 Mar 115(4) 523-527
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Introduction

• Significant proteinuria is an important finding
  in pregnancy
• Presence of proteinuria, not severity
• Detection of new onset proteinuria important
• Screening test
• High false positive and negatives

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• Urine dipstick screening test
• When do you proceed to further tests if the dip
  is positive?
• Quantitated by
• -24-hr urine
• -Protein/creatinine ratio (PCR)
• -Albumin/creatinine ratio (ACR)

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Hypothesis

• That the use of an automated quantitative urine
  analyser in the antenatal clinic would help
  diagnose the true positives for significant
  proteinuria.

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Aim

• To compare the efficacy of the ACR (DCA 2000)
  measurement in detection of significant
  proteinuria in the outpatient setting
• Compared to - automated dipstick
• - PCR
• - 24-hr urine

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Methods

• Inclusions
• High risk antenatal clinic
• gt 20/40 single or multiple gestation
• 1 protein on dipstick on MSU
• New onset proteinuria
• Control group with negative or trace proteinuria
  on dipstick

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• Exclusions
• Positive MSU culture for UTI
• Underlying proteinuric renal disease
• Diabetics with a abnormal ACR in trimester one

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• MSU obtained
• Separated into 3 aliquots ( PCR, ACR, MSU for
  culture sensitivity)
• 24-hr urine performed ( total protein
  concentration / 24hr, creatinine excretion)

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• The same patient could be recruited multiple
  times (gt 14 day interval)
• All recruited by a single research midwife
• Recruited over 19 months
• Quality control
• Demographic details collected, as were the test
  results
• Results entered into Access database

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Statistics

• Power calculation performed to obtain numbers for
  recruitment
• Descriptive statistics
• Screening statistics ROC curves likelihood
  ratios, with confidence intervals

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Results

• Total number recruited 188
• MSU positive 3
• 24hr urine not completed 35
• N 150
• Proteinuria ? 1 100
• Proteinuria neg or trace 50

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Results - Demographics
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Results- Demographics
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Results Medical Details
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• Ten women were recruited twice
• Median interval 45 days (range 18-96)
• 25 (17.9) developed pre-eclampsia
• 13 (8.7) had significant proteinuria

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Results-ROC ACR, PCR, 24-hr urine
ROC areas (95CI) Albumin/creatinine (DCA 2000)
0.991 (0.974 - 1.000) Protein/creatinine 0.988
(0.971 - 1.000) Urine dipstick
0.913 (0.833 - 0.993)
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Results- measures of diagnostic accuracy
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Results- measures of diagnostic accuracy
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Discussion

• ACR accurate ( at 8.0 mg/mmol)
• May provide improvement in patient flow
  management
• ACR should be strongly considered in high risk
  ANC
• Unable to comment on those with nonsignificant
  proteinuria and development of pre-eclampsia

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Discussion-limitations

• Sample size- 13 (8) with significant proteinuria
• 25 (17.5) developed pre-eclampsia
• Women were assessed in the type of environment in
  which the test will be used
• Accurate and efficient

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Conclusion

• Both the ACR ( DCA 2000) and PCR are effective
  tests for identifying significant proteinuria
  when compared to the 24-hr protein in the
  outpatient setting.
• The ACR has the advantage of an immediate result,
  which can facilitate patient flow and minimise
  additional testing

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Acknowledgements

• B Pullar Our immense gratitude for her
  enthusiasm and perserverance with recruitment
• All clinic midwives for their support and help
  with recruitment
• Women who participated