Urinary protein-to-creatinine ratio in pregnant women after dipstick testing: prospective observational study

The diagnostic Accuracy of Visual versus automated dipstick proteinuria testing in Pregnancy: A systematic review and Meta-Analysis

OBJECTIVE

To evaluate the diagnostic accuracy of point-of-care (POC) tests for detecting proteinuria in pregnant women.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

MEDLINE and EMBASE databases were searched from inception to 13 November 2020.

ELIGIBILITY CRITERIA AND DATA ANALYSIS

Included studies measured the sensitivity and specificity ofPOC proteinuria testing compared to laboratory reference standards (protein-creatinine ratio (PCR), 24-hour urine collection). Bivariate meta-analyses determined pooled sensitivity and specificity. Random-effects inverse-variance model determinedheterogeneity.

MAIN OUTCOME MEASURES

The primary outcome was overall sensitivity and specificity, stratified by method of POC testing and reference standard. Secondary outcomes were sensitivity and specificity within thesubgroupstest brand, reference standard, and hypertension status.

RESULTS

1078 studies were identified, 17 studies comprising 23 comparisons were included. The meta-analysis included 13 studies with 19 comparisons. Pooled sensitivity and specificity of visual dipsticks against PCR was 72 % (95 % CI: 56 % to 84 %) and 92 % (95 % CI: 76 % to 98 %), respectively. Pooled sensitivity and specificity of visual dipsticks against 24-hour collection was 69 % (55 % to 80 %) and 70 % (51 % to 84 %), respectively. Pooled sensitivity and specificity for automated readers against PCR was 73 % (53 % to 86 %) and 91 % (83 % to 95 %), respectively. Pooled sensitivity and specificity of automated readers against 24-hour collection was 65 % (42 % to 83 %) and 82 % (46 % to 96 %), respectively.

CONCLUSION

Visual dipsticks have comparable accuracy to automated readers, yet are notadequate as a rule-out test for proteinuria. Proteinuria POC testing maybe beneficial inantenatal care when repeatfollow-up tests are performed. PROSPERO Registration Number: CRD42021231914.

Establishment, verification, and application of concentration intervals corresponding to dipstick grades for urinary protein

BACKGROUND

To address the situation that the accuracy of concentration intervals (CI) corresponding to dipstick grades is not given by the manufacturers or literature, we developed a method that determined reasonable dipstick grades with concentration intervals (GCIs) based on the percent agreement (PA) and discussed the GCI application to comparability among currently dipstick tests.

METHODS

By comparing the results of 2 dipstick tests (iChem and KU-500) with the quantitative test (AU5800), the GCIs were verified and established based on the PAs, which were calculated and used as an indicator of GCI's accuracy. The overlap (percent) between the 2 GCIs with the same grade (2 dipstick devices), was calculated and used to evaluate the agreement between their test results.

RESULTS

After verification and adjustment, the GCI and PA combinations for iChem Velocity were as follows: - (<0.1 g/l, 85 %), ± (0.1-0.3 g/l, 66 %), 1+ (0.3-1 g/l, 78 %), 2+ (1-3 g/l, 74 %), 3+ (3-6 g/l, 77 %), and 4+ (≥6 g/l, 84 %). The determined GCI and PA combinations for KU-500 were: - (<0.1.2 g/l, 75 %), ± (0.12-0.5 g/l, 63 %), 1+ (0.5-1.2 g/l, 69 %), 2+ (1.2-3.2 g/l, 76 %), and 3+ (≥3.2 g/l, 82 %). The GCI overlaps between the 2 dipstick devices were - (83 %), ± (45 %), 1+ (56 %), 2+ (82 %), and 3+ or ≥3+ (94 %). The overall overlap was 72 %. Since the overlaps ± (45 %) and 1+ (56 %) were within the overlap reject limit for any grade (70 %), and the overall overlap (72 %) was within the overall overlap reject limit (80 %), the test results of the 2 devices were not comparable.

CONCLUSIONS

GCIs can be verified and established correctly based on PAs, and industry standards for dipstick tests can be established based on GCIs and PAs. Comparability between dipstick devices, historical data, and literature data can be roughly determined based on the overlap.

Proteinuria during pregnancy: definition, pathophysiology, methodology, and clinical significance

Qualitative and quantitative measurement of urine protein excretion is one of the most common tests performed during pregnancy. For more than 100 years, proteinuria was necessary for the diagnosis of preeclampsia, but recent guidelines recommend that proteinuria is sufficient but not necessary for the diagnosis. Still, in clinical practice, most patients with gestational hypertension will be diagnosed as having preeclampsia based on the presence of proteinuria. Although the reference standard for measuring urinary protein excretion is a 24-hour urine collection, spot urine protein-to-creatinine ratio is a reasonable "rule-out" test for proteinuria. Urine dipstick screening for proteinuria does not provide any clinical benefit and should not be used to diagnose proteinuria. The classic cutoff cited to define proteinuria during pregnancy is a value of >300 mg/24 hours or a urine protein-to-creatinine ratio of at least 0.3. Using this cutoff, the rate of isolated proteinuria in pregnancy may reach 8%, whereas preeclampsia occurs among 3% to 8% of pregnancies. Although this threshold is widely accepted, its origin is not based on evidence on adverse pregnancy outcomes but rather on expert opinion and results of small studies. After reviewing the available data, the most important factor that influences maternal and neonatal outcome is the severity of blood pressures and presence of end organ damage, rather than the excess protein excretion. Because the management of gestational hypertension and preeclampsia without severe features is almost identical in frequency of surveillance and timing of delivery, the separation into 2 disorders is unnecessary. If the management of women with gestational hypertension with a positive assessment of proteinuria will not change, we believe that urine assessment for proteinuria is unnecessary in women who develop new-onset blood pressure at or after 20 weeks' gestation. Furthermore, we do not recommend repeated measurement of proteinuria for women with preeclampsia, the amount of proteinuria does not seem to be related to poor maternal and neonatal outcomes, and monitoring proteinuria may lead to unindicated preterm deliveries and related neonatal complications. Our current diagnosis of preeclampsia in women with chronic kidney disease may be based on a change in protein excretion, a baseline protein excretion evaluation is critical in certain conditions such as chronic hypertension, diabetes, and autoimmune or other renal disorders. The current definition of superimposed preeclampsia possesses a diagnostic dilemma, and it is unclear whether a change in the baseline proteinuria reflects another systemic disease such as preeclampsia or whether women with chronic disease such as chronic hypertension or diabetes will experience a different "normal" pattern of protein excretion during pregnancy. Finally, limited data are available regarding angiogenic and other biomarkers in women with chronic kidney disease as a potential aid in distinguishing the worsening of baseline chronic kidney disease and chronic hypertension from superimposed preeclampsia.

Diagnostic accuracy of urine dipstick tests for proteinuria in pregnant women suspected of preeclampsia: A systematic review and meta-analysis

OBJECTIVES

Dipstick tests are frequently used as bedside proteinuria tests to evaluate women suspected of preeclampsia and may inform diagnosis in low resource settings lacking laboratory facilities. This systematic review and meta-analysis aimed to (1) estimate the diagnostic accuracy of urine dipsticks in diagnosing proteinuria, (2) compare performance of different dipstick types and (3) estimate their related costs.

METHODS

MEDLINE and EMBASE were searched up to August 1, 2020 for primary studies with cross-sectional diagnostic accuracy data on dipstick test(s) compared to a laboratory reference standard (24-hour protein ≥ 300 mg or protein-creatinine ratio ≥ 30 mg/mmol) in pregnant women ≥ 20 weeks of gestation suspected of preeclampsia. Risk of bias and applicability was assessed with QUADAS-2. Data were analysed using a bivariate model with hierarchical addition of covariates for subgroups.

RESULTS

Nineteen studies were included. Protein-only dipsticks at 1 + threshold had a pooled sensitivity of 0.68 [95%CI: 0.57-0.77] and specificity of 0.85 [95% CI: 0.73-0.93] (n = 3700 urine samples, 18 studies). Higher specificity was found with automatedly (0.93 [95% CI: 0.82-0.98]) compared to visually (0.81 [95% CI: 0.65-0.91]) read dipsticks, whereas sensitivity was similar and costs were higher. The use of albumin-creatinine ratio (ACR) dipsticks was only reported in two studies and did not improve accuracy. Heterogeneity in study design and prevalence of preeclampsia amongst studies complicated interpretation of pooled estimates.

CONCLUSION

Urine dipsticks performed poorly at excluding preeclampsia in hypertensive pregnant women. Further development of accurate and low-cost bedside proteinuria tests is warranted.

Progression from isolated gestational proteinuria to preeclampsia with severe features

INTRODUCTION

The association between the degree of isolated gestational proteinuria and preeclampsia with severe features and other placental-mediated complications is controversial. The aim of this study was to evaluate whether a higher isolated proteinuria level is associated with an increased frequency of preeclampsia with severe features.

MATERIAL AND METHODS

This retrospective cohort study included pregnant women who were past 24 weeks of gestation and were diagnosed as having new-onset proteinuria ≥300 mg in a 24-h urine collection. Exclusion criteria included diagnosis of preeclampsia within 72 h from admission, chronic renal disease or chronic hypertension. The study population was divided into tertiles by proteinuria level and the association with preeclampsia with severe features was assessed in both bivariable and multivariable analysis. The main outcome measures was the development of preeclampsia with severe features.

RESULTS

Overall, 165 women were diagnosed with isolated gestational proteinuria, and 38 (23.0%) of them developed preeclampsia with severe features. Women in the increasing proteinuria tertile were more likely to develop preeclampsia with severe features (5.5%, 21.8%, 41.8%, respectively; p = 0.004). A multivariable logistic regression model controlling for background characteristics as well as gestational age at diagnosis, blood pressure, and kidney and liver function tests showed an increased risk of 14% to develop preeclampsia with severe features for every 500-mg rise in proteinuria level (adjusted odds ratio = 1.14, 95% confidence interval 1.03-1.27).

CONCLUSIONS

A higher isolated gestational proteinuria level was associated with an increased risk to develop preeclampsia with severe features among pregnant women past 24 weeks of gestation.

Study of Combination of Nanoherbal Andaliman (Zanthoxylum acanthopodium) and Extra Virgin Olive Oil (EVOO) Effects in the Expression of Malondialdehyde (MDA), Heat Shock Protein-70 (HSP70) and Placental Histology of Preeclamptic Rats

Background: Pre-eclampsia (PE) contributes to the second cause of maternal death in Indonesia. Andaliman is a typical spice of the Batak ethnic in Northern Sumatera Province, Indonesia. This study aimed to explore the potential of novel herbal medicine compound of nanoherbal andaliman and extra virgin olive oil (EVOO) as PE treatment. Methods: Nanoherbal andaliman was generated using High-energy Milling (HEM). The treatments were divided into the following five groups: K- (control): pregnant rats; K+: PE model rats; P1: PE model rats + 0.45 g of EVOO/200 g BW on the 13th–19th day of pregnancy; P2: PE model rats + nanoherbal andaliman 100 mg/200 g BW on the 13th– 19th day of pregnancy; and P3: PE model rats + combination of 0.45 EVOO/200 g BW and nanoherbal andaliman 100 mg/200 g BW on the 13th–19th day of pregnancy. Rats were dissected on the 20th day of pregnancy. The observed parameters were blood pressure, proteinuria, malondialdehyde (MDA), Heat Shock Protein-70 HSP-70 and histology of placenta. Results: A significant difference was noticed (p<0.05) in blood pressure, proteinuria, foetal weight, haematocrit, erythrocytes and trophoblastic cells after the administration of combined nanoherbal andaliman and EVOO. No significant differences in placental weight, foetal number, leukocytes, MDA and HSP-70 were found (p>0.05). Conclusion: The combination of nanoherbal andaliman and EVOO decreased systolic blood pressure and induced the expression of MDA and HSP-70, as well as placental histology of pre-eclamptic rats.

Direct laboratory evidence that pregnancy-induced hypertension might be associated with increased catecholamines and decreased renalase concentrations in the umbilical cord and mother’s blood

Background

Renalase (RNL) is a controversial enzyme as to whether it oxidizes catecholamines (CAs) (as is generally accepted) in the blood or not. CAs (dopamine [DPMN], epinephrine [EPI] and norepinephrine [NEPI]) are associated with hypertension, including pregnancy-induced hypertension, which occurs in 8–10% of all pregnancies. Therefore, the aim of the study was to compare CAs and renalase concentration in (i) normotensive controls (C), (ii) patients with preeclampsia (PE) and (iii) patients with severe preeclampsia (SPE), which is one of the well-known symptoms of hypertension.

Methods

This case-control study involved 90 women divided into three groups – 30 C, 30 PE and 30 SPE – whose age and body mass indexes (BMIs) were similar. A total of 270 blood samples (90 maternal samples, 90 umbilical cord artery samples and 90 umbilical cord vein samples) were obtained. CAs and RNL concentrations of the biological samples were measured by enzyme-linked immunosorbent assay (ELISA).

Results

Comparing the amounts of CAs, RNL and systolic blood pressure (SBP)/diastolic blood pressure (DBP) between healthy control pregnant women and pregnant women with PE and SPE (SBP/DBP was 120/80 mm Hg for C, above 140/90 mm Hg for PE and above 160/110 mm Hg for SPE), the levels of CAs were significantly increased whereas RNL was reduced. The correlation between SBP/DBP and the amount of RNL in pregnant women with PE and SPE was negative.

Conclusions

These novel results are evidence that hypertension seen in PE and SPE is directly related to increased levels of CAs and reduced RNL concentrations. The use of RNL preparations may be preferred in future to prevent maternal and perinatal morbidity and mortality due to pregnancy-induced hypertension.

Impact of random urine proteinuria on maternal and fetal outcomes of pregnancy: a retrospective case-control study

BACKGROUND/AIMS

Proteinuria is associated with hypertension and preeclampsia in pregnancy. However, the impact of random urine proteinuria on fetal and maternal outcomes has not been established. We investigated the influence of random urine proteinuria on the clinical outcomes of pregnancy.

METHODS

From January 2008 to December 2010, 2,822 patients were retrospectively studied. A total of 536 pregnant women with proteinuria in random urine and matched controls without proteinuria via propensity score matching were analyzed. Proteinuria was checked by the dipstick method.

RESULTS

The patients' mean age was 33.0 ± 4.7 years, and the mean gestational age was 235.6 ± 50.6 days on admission. The prevalence of hypertension and chronic kidney disease was 2.4% (n = 67) and 1.0% (n = 29), respectively. Women with random urine proteinuria showed higher blood urea nitrogen levels and a higher incidence of hematuria. These women also had a higher incidence of preeclampsia, preterm labor, premature rupture of membranes, and intrauterine growth restriction. Proteinuria was strongly correlated with preeclampsia in both propensity score matching (p < 0.001, r = 0.783) and unmatched whole samples (p < 0.001, r = 0.851).

CONCLUSIONS

These findings suggest that random urine proteinuria is associated with preeclampsia, preterm labor, premature rupture of membrane, and intrauterine growth restriction.