Urinary calcium/creatinine ratio as a predictor of preeclampsia

Pregnancy urine biomarkers for effectively preeclampsia prediction: a systematic review and meta-analysis

Preeclampsia (PE) is a common multi-organ disorder in pregnancy. Urine as a source for test samples is noninvasive and easy to obtain. This study followed the Priority Reporting Project for Systematic Evaluation and Meta-Analysis protocol. We searched PubMed and Web of Science databases for studies relating to urine biomarker analysis for PE from inception to the 28th of February 2023. The Chi-squared test was utilized to evaluate the statistical heterogeneity of the results. The combined sensitivity, combined specificity, combined positive likelihood ratio, combined negative likelihood ratio, combined diagnostic odds ratio for urine analysis in the context of PE were calculated. Sixty-five studies were eventually included in the final analysis. In only hypertensive disorders of pregnancy (HDP) pregnant women, the the area under the summary receiver operating characteristic curve (AUC) of urine analysis to predict PE was 0.93 (0.91-0.95). The results show that spot random urine analysis or shortened-hour urinary analysis for the diagnosis of PE is a credible alternative method when 24-h urine collection is difficult to complete. The protein/creatinine ratio from spot random urine analysis may be an effective biomarker of the further progression of HDP into PE.

A cohort study on use of the spot urine calcium-creatinine ratio for prediction of antepartum preeclampsia among high-risk pregnant women in Delta State, Nigeria

Background/Aim: Preeclampsia is a multisystemic disorder, which significantly contributes to maternal and fetal morbidity and mortality, especially in developing countries where it accounts for about one-third of maternal mortality cases. Predicting its occurrence will reveal a sizeable population of pregnant women who will undoubtedly benefit from prevention. The ideal screening marker for the disease is still being investigated. The urine calcium-creatinine ratio (CCR) is an inexpensive, simple, and easily assayed biomarker. This study determined the accuracy of the spot urinary calcium-creatinine ratio in predicting the occurrence of preeclampsia. Methods: This was a prospective cohort study conducted in Delta State, which involved four healthcare facilities in Nigeria. A total of 138 pregnant women between 8 and 18 weeks gestation were recruited. Urine samples were obtained at 18 weeks to assay their CCR, and patients were followed up weekly for blood pressure measurement and dipstick urinalysis until delivery. Results: The mean spot urine CCR in this study was 0.225 (0.101). It was significantly lower in women who developed preeclampsia compared to normotensive women (P < 0.001). Multiple logistics regression analysis showed that the association between urine CCR and occurrence of preeclampsia was statistically significant. At a receiver operating characteristic cutoff of ≤ 0.1065, CCR had a sensitivity of 75%, specificity of 91.3%, positive predictive value (PPV) of 35.3%, and negative predictive value (NPV) of 98.3%. The low PPV of 35.3% can be explained by the low prevalence of preeclampsia (5.78%) in the study population. Conclusion: In conclusion, the poor PPV of the urine CCR was due to the low prevalence of preeclampsia in the study. However, in considering all women at risk, urine CCR may be a good prognostic marker when the illness prevalence is substantial.

Paper-based assays for urine analysis

A transformation of the healthcare industry is necessary and imminent: hospital-centered, reactive care will soon give way to proactive, person-centered care which focuses on individuals' well-being. However, this transition will only be made possible through scientific innovation. Next-generation technologies will be the key to developing affordable and accessible care, while also lowering the costs of healthcare. A promising solution to this challenge is low-cost continuous health monitoring; this approach allows for effective screening, analysis, and diagnosis and facilitates proactive medical intervention. Urine has great promise for being a key resource for health monitoring; unlike blood, it can be collected effortlessly on a daily basis without pain or the need for special equipment. Unfortunately, the commercial rapid urine analysis tests that exist today can only go so far-this is where the promise of microfluidic devices lies. Microfluidic devices have a proven record of being effective analytical devices, capable of controlling the flow of fluid samples, containing reaction and detection zones, and displaying results, all within a compact footprint. Moving past traditional glass- and polymer-based microfluidics, paper-based microfluidic devices possess the same diagnostic ability, with the added benefits of facile manufacturing, low-cost implementation, and disposability. Hence, we review the recent progress in the application of paper-based microfluidics to urine analysis as a solution to providing continuous health monitoring for proactive care. First, we present important considerations for point-of-care diagnostic devices. We then discuss what urine is and how paper functions as the substrate for urine analysis. Next, we cover the current commercial rapid tests that exist and thereby demonstrate where paper-based microfluidic urine analysis devices may fit into the commercial market in the future. Afterward, we discuss various fabrication techniques that have been recently developed for paper-based microfluidic devices. Transitioning from fabrication to implementation, we present some of the clinically implemented urine assays and their importance in healthcare and clinical diagnosis, with a focus on paper-based microfluidic assays. We then conclude by providing an overview of select biomarker research tailored towards urine diagnostics. This review will demonstrate the applicability of paper-based assays for urine analysis and where they may fit into the commercial healthcare market.

Evaluation of the value of calcium to creatinine ratio for predicting of pre-eclampsia

INTRODUCTION

Pre-eclampsia is one of the most serious complications in pregnancy and is one of the major causes of maternal death. Therefore, its prediction has special importance and many studies have been performed on different materials, which may be useful for its prediction.

OBJECTIVE

The purpose of the present study is to evaluate the calcium to creatinine ratio for the prediction of pre-eclampsia.

METHOD

A prospective cohort study was performed on 150 pregnant women, who were aged from 15 to 35 years. A single urine sample was obtained at 20-24 weeks of gestation for measurement of urine calcium to creatinine ratio. The women were then monitored for delivery and this ratio was compared between the women with and without pre-eclampsia.

RESULTS

Mean urine calcium of pre-eclamptic women was significantly lower than normotensive women (179 ± 35 mg/dl vs 272 ± 59 mg/dl, P < 0.001). Mean calcium to creatinine ratio was significantly lower in pre-eclamptic women (0.07 ± 0.007 vs 0.16 ± 0.006, P < 0.001). The optimal cut off point for calcium to creatinine ratio was calculated to be 0.071 with a sensitivity of 77% and specificity of 78%.

CONCLUSION

Urine calcium and calcium to creatinine ratio are lower in pre-eclamptic women and may be used as a screening test for the prediction of pre-eclampsia.

Urine analysis in microfluidic devices

Microfluidics has attracted considerable attention since its early development in the 1980s and has experienced rapid growth in the past three decades due to advantages associated with miniaturization, integration and automation. Urine analysis is a common, fast and inexpensive clinical diagnostic tool in health care. In this article, we will be reviewing recent works starting from 2005 to the present for urine analysis using microfluidic devices or systems and to provide in-depth commentary about these techniques. Moreover, commercial strips that are often treated as chips and their readers for urine analysis will also be briefly discussed. We start with an introduction to the physiological significance of various components or measurement standards in urine analysis, followed by a brief introduction to enabling microfluidic technologies. Then, microfluidic devices or systems for sample pretreatments and for sensing urinary macromolecules, micromolecules, as well as multiplexed analysis are reviewed, in this sequence. Moreover, a microfluidic chip for urinary proteome profiling is also discussed, followed by a section discussing commercial products. Finally, the authors' perspectives on microfluidic-based urine analysis are provided. These advancements in microfluidic techniques for urine analysis may improve current routine clinical practices, particularly for point-of-care (POC) applications.

Increases in urinary creatinine and blood pressure during early pregnancy in pre-eclampsia

BACKGROUND

It is important to predict the development of pre-eclampsia (PE) during early pregnancy to prevent its occurrence later on. In this study, we studied urinary biochemical parameters and blood pressure (BP) during and after pregnancy to find useful parameters for predicting PE.

METHODS

A case-control study was performed in 25 PE patients and 172 normotensive pregnant women. Twelve biochemical parameters were measured in spot urine, and the systolic and diastolic BPs were measured using an automated device during pregnancy and six to eight weeks after birth.

RESULTS

A multiple logistic regression analysis showed that the combinations of urinary creatinine (Cr) and systolic BP (SBP) in the first trimester of pregnancy (8.9 +/- 2.6 weeks), and of urinary inorganic phosphorus (IP)/Cr and SBP in the second trimester of pregnancy (19.0 +/- 1.6 weeks) were useful for predicting PE. The area under the curve in the receiver operator characteristic curve of the combination of urinary Cr and SBP in the first trimester was 0.85 (95% confidence interval [CI] 0.74-0.96), and that of the combination of urinary IP/Cr and SBP in the second trimester was 0.91 (95% CI: 0.86-0.97). When used 249 mg/dL in urinary Cr and 128 mmHg in SBP as their cut-off points, the combination in the first trimester increased the accuracy (sensitivity 75% and specificity 95%) in predicting PE, as compared with that of urinary Cr (29%, 99%) or SBP (50%, 98%).

CONCLUSIONS

Combination of urinary Cr and SBP in early pregnancy and that of urinary IP/Cr and SBP in mid-pregnancy are useful for the prediction of PE.

Urinary calcium and magnesium excretion relates to increase in blood pressure during pregnancy

OBJECTIVE

Pregnancy-induced hypertension and preeclampsia are serious clinical manifestations during late pregnancy and the cause for increased maternal and foetal morbidity and mortality. The pathogenesis is unknown but experience from treatment schemes suggests that minerals may be of importance. Mineral homeostasis is influenced by acid-base conditions. The aim of the study was to elucidate the relation between acid-base balance, urinary mineral excretion and blood pressure during pregnancy.

DESIGN

A prospective observational study of a general population.

MATERIALS AND METHODS

The study was performed at the Midwife Health Center in Borås, Sweden, where practically all pregnant subjects in the catchment area are registered. First time pregnant subjects (n = 123) were voluntarily recruited without exclusion criteria. A 24 h urine sample was collected at pregnancy week 12 and analyzed for creatinine, calcium, magnesium, and urea as a proxy for acid conditions. Blood pressure was recorded every 2-3 weeks until delivery.

RESULTS

There was a relation between the excretion of urea and calcium and magnesium at week 12. A blood pressure increase was found after pregnancy week 30 but only among subjects who had a high excretion of calcium and magnesium at week 12.

CONCLUSIONS

If an increase in blood pressure during the later part of pregnancy a risk indicator for preeclampsia, the results suggest that an excessive secretion of calcium leading to a functional deficit might be a risk indicator for gestational hypertension and preeclampsia. Intervention experiments are required to assess this hypothesis.

Spatiotemporal organization of pre-mRNA splicing proteins in plants

The general organization ofeukaryotic nuclei, including plant nuclei, into functional domains is now widely recognized. Conventional immunocytochemistry and visualization of proteins fused to fluorescent proteins (FP) have revealed that in plants, RNA and protein components of pre-mRNA splicing are spatially organized depending on the stage of cell cycle, development, and the cell's physiological state. Application of some of the latest microscopy techniques, which reveal biophysical properties such as diffusion and interaction properties of proteins, has begun to provide important insights into the functional organization of spliceosomal proteins in plants. Although some progress has been made in understanding the spatial and temporal organization of splicing machinery in plants, the mechanisms that regulate this organization and its functional consequences remain unresolved.

Urinary calcium excretion in severe preeclampsia and eclampsia

Urinary calcium levels in women with mild preeclampsia, severe preeclampsia and eclampsia were evaluated in this study. We collected 24-h urine samples from 35 mild preeclamptic (Group 1), 30 severe preeclamptic (Group 2), and 17 eclamptic patients (Group 3). The control group (Group 4) consisted of 35 healthy pregnant women. Serum levels of total calcium and creatinine, and urinary calcium were measured. These values were compared in the four groups. The mean maternal age and parity were similar in all groups. There were no statistically significant differences in the serum levels of total calcium and creatinine (p>0.05). Urinary calcium excretion in patients with preeclampsia and eclampsia was significantly lower than in controls (p<0.0001). Urinary calcium levels between mild preeclampsia and severe pre-eclampsia, and severe preeclampsia and eclampsia were similar (p>0.05), but were lower in eclampsia than in mild preeclampsia (p<0.05). In conclusion, urinary calcium excretion is reduced in patients with severe preeclampsia or eclampsia. However, the decrease in urinary calcium excretion cannot be used to identify the severity of preeclampsia, or to predict impending eclampsia.

Calcium Homeostasis in Human Placenta: Role of Calcium‐Handling Proteins

The human placenta is a transitory organ, representing during pregnancy the unique connection between the mother and her fetus. The syncytiotrophoblast represents the specialized unit in the placenta that is directly involved in fetal nutrition, mainly involving essential nutrients, such as lipids, amino acids, and calcium. This ion is of particular interest since it is actively transported by the placenta throughout pregnancy and is associated with many roles during intrauterine life. At term, the human fetus has accumulated about 25-30 g of calcium. This transfer allows adequate fetal growth and development, since calcium is vital for fetal skeleton mineralization and many cellular functions, such as signal transduction, neurotransmitter release, and cellular growth. Thus, there are many proteins involved in calcium homeostasis in the human placenta.

Prediction of preeclampsia: can it be achieved?

In this review, the various biochemical tests that have been proposed for the prediction of preeclampsia are described and evaluated. Placenta hormone markers do not predict future disease. They denounce the early placental changes that are part of the evolving disease and only predict the imminent of preeclamptic syndrome. This explains why tests are better predictors when preeclampsia supervenes shortly, and why screening in the first trimester is unlikely to work as well as in the second trimester. The use of multiple markers in the screening should reflect different aspects of the disease process and could increase the specificity and sensitivity of the screening and work on different etiologic factors. The possible use of second-trimester biochemical screening to predict the risk of preeclampsia remains to be investigated in the high-risk population.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians

LEARNING OBJECTIVES

After completion of this article, the reader should be able to list the various theories on the etiology of preeclampsia, to relate the various risk factors for the development of preeclampsia, and to describe the various screening tests for preeclampsia.

Calcium to creatinine ratio in a spot sample of urine for early prediction of pre-eclampsia

OBJECTIVES

Based on the fact that urinary calcium excretion decreases in pre-eclampsia, this study was designed to determine the predictive value of calcium to creatinine ratio in a spot urine sample.

METHODS

The calcium to creatinine ratio was measured in a spot urine sample of 102 normotensive women at 20-24 weeks' gestation who attended the prenatal care clinic of the Shiraz University of Medical Sciences. The women were followed-up until delivery and grouped according to pre-eclampsia occurrence. The prevalence of pre-eclampsia was measured and compared with the calcium to creatinine ratio.

RESULTS

Ninety-four women remained normotensive during pregnancy and eight developed pre-eclampsia. Mean age, gestational age at the beginning of the study, and gestational age at delivery did not differ significantly between the two groups. Mean urinary calcium concentration (15.9+/-8.5 mg/dl in normotensive vs. 10.2+/-7.5 mg/dl in pre-eclamptic women), and mean birth weight (3192+/-336.3 g vs. 2712+/-468.9 g) were significantly lower in pre-eclamptic patients (P=0.03 and 0.005, respectively). Mean calcium to creatinine ratio was also significantly lower in the pre-eclamptic group (P<0.03).

CONCLUSIONS

Single urine calcium to creatinine ratio may be an effective method for screening women at greatest risk for pre-eclampsia.