Maternal Serum Uric Acid as a Predictor of Severity of Hypertensive Disorders of Pregnancy: A Prospective Cohort Study

The Impact of Serum Uric Acid Levels on Hypertensive Disorders of Pregnancy in Advanced Maternal Age Women: A Retrospective Study from a Single Center in China

BACKGROUND In many countries, including China, women are delaying pregnancy until later in life; therefore, hypertensive disorders of pregnancy (HDP) are increasing. This retrospective study from a single center in China aimed to evaluate the association between serum uric acid (SUA) levels and HDP in 288 women of advanced maternal age >35 years. MATERIAL AND METHODS A total of 780 pregnant women of advanced maternal age were included in the study - 288 were had HDP (including gestational hypertension and preeclampsia) and 492 had normal blood pressure using 1: 2 (84: 168) propensity score matching. SUA (collected before 20 weeks' gestation) and HDP incidence in advanced maternal age women were assessed using multivariate logistic modeling and 3 propensity score-based methods. RESULTS Median patient age was 37 years. The risk of developing HDP increases with higher SUA (30.19% vs 13.65%, P<0.001). In the PS-matched cohort, the risk ratio (OR) for HDP with high uric acid after adjusting for confounders was 2.88 (95% CI: 1.44-5.75, P=0.0027). It has been demonstrated that high uric acid is strongly associated with HDP incidence in both the crude population (OR=3.43, 95% CI: 2.01-4.66, P<0.0001) and the weighted cohorts (OR=3.62, 95% CI: 2.81-4.66, P<0.0001). As a successive variable, after adjusting for the clinical confounders, a 1-SD increase in SUA was related to a 135% increased risk of HDP (OR=2.35; 95% CI: 1.57-3.50; P<0.0001) based on the fully adjusted model. There were similar conclusions in the sensitivity analysis. CONCLUSIONS There was a significant association between SUA and HDP in women of advanced maternal age, supporting the importance of early detection of SUA in pregnant women.

The relation between serum uric acid and severity of preeclampsia in pregnant women: a cross-sectional study

Introduction

There are conflicting data regarding the relation between serum uric acid (SUA) and severity of preeclampsia (PE). The aim of the study was to assess the relation between SUA and the severity of PE.

Material and methods

A total of 110 pregnant women were studied; 55 with mild PE were compared to 55 women with severe PE in this cross-sectional study, which was conducted in Maternity Hospital. After thorough evaluation and renal function tests, spot urine samples were taken from participants for the protein/creatinine ratio. The urine proteins were measured by the Biuret colorimetric method. The urine creatinine was measured by the modified Jaffe test. The serum uric acid was measured by the enzymatic method. The collected participants' data were statistically analysed, and Pearson's coefficient was used to detect the relation between SUA and severity of PE.

Results

The serum uric acid was significantly higher in the severe PE group (7.65 ±0.61 mg/dl) compared to the mild PE group (5.26 ±0.79 mg/dl), (p = 0.04). There were significant positive relations between the SUA and both the systolic and diastolic blood pressures [r = 0.27 (p = 0.045) and r = 0.483 (p < 0.001), respectively] in the severe PE group. There were also significant positive relations between the SUA and both the systolic and diastolic blood pressures [r = 0.359 (p = 0.007) and r = 0.429 (p = 0.001), respectively] in the mild PE group.

Conclusions

There were significant positive relations between the SUA and both the systolic and dia-stolic blood pressures in the severe PE group. This study recommends the use of SUA as a reliable marker of the severity of PE.

Predictive Model for Preeclampsia Combining sFlt-1, PlGF, NT-proBNP, and Uric Acid as Biomarkers

N-terminal pro-brain natriuretic peptide (NT-proBNP) and uric acid are elevated in pregnancies with preeclampsia (PE). Short-term prediction of PE using angiogenic factors has many false-positive results. Our objective was to validate a machine-learning model (MLM) to predict PE in patients with clinical suspicion, and evaluate if the model performed better than the sFlt-1/PlGF ratio alone. A multicentric cohort study of pregnancies with suspected PE between 24+0 and 36+6 weeks was used. The MLM included six predictors: gestational age, chronic hypertension, sFlt-1, PlGF, NT-proBNP, and uric acid. A total of 936 serum samples from 597 women were included. The PPV of the MLM for PE following 6 weeks was 83.1% (95% CI 78.5−88.2) compared to 72.8% (95% CI 67.4−78.4) for the sFlt-1/PlGF ratio. The specificity of the model was better; 94.9% vs. 91%, respectively. The AUC was significantly improved compared to the ratio alone [0.941 (95% CI 0.926−0.956) vs. 0.901 (95% CI 0.880−0.921), p < 0.05]. For prediction of preterm PE within 1 week, the AUC of the MLM was 0.954 (95% CI 0.937−0.968); significantly greater than the ratio alone [0.914 (95% CI 0.890−0.934), p < 0.01]. To conclude, an MLM combining the sFlt-1/PlGF ratio, NT-proBNP, and uric acid performs better to predict preterm PE compared to the sFlt-1/PlGF ratio alone, potentially increasing clinical precision.

The Association between Gut Microbiome and Pregnancy-Induced Hypertension: A Nested Case–Control Study

(1) Background: Pregnancy-induced hypertension (PIH) is associated with obvious microbiota dysbiosis in the third trimester of pregnancy. However, the mechanisms behind these changes remain unknown. Therefore, this study aimed to explore the relationship between the gut microbiome in early pregnancy and PIH occurrence. (2) Methods: A nested case–control study design was used based on the follow-up cohort. Thirty-five PIH patients and thirty-five matched healthy pregnant women were selected as controls. The gut microbiome profiles were assessed in the first trimester using metagenomic sequencing. (3) Results: Diversity analyses showed that microbiota diversity was altered in early pregnancy. At the species level, eight bacterial species were enriched in healthy controls: Alistipes putredinis, Bacteroides vulgatus, Ruminococcus torques, Oscillibacter unclassified, Akkermansia muciniphila, Clostridium citroniae, Parasutterella excrementihominis and Burkholderiales bacterium_1_1_47. Conversely, Eubacterium rectale, and Ruminococcus bromii were enriched in PIH patients. The results of functional analysis showed that the changes in these different microorganisms may affect the blood pressure of pregnant women by affecting the metabolism of vitamin K₂, sphingolipid, lipid acid and glycine. (4) Conclusion: Microbiota dysbiosis in PIH patients begins in the first trimester of pregnancy, and this may be associated with the occurrence of PIH. Bacterial pathway analyses suggest that the gut microbiome might lead to the development of PIH through the alterations of function modules.

Relationship between maternal serum uric acid level and preeclampsia with or without severe features

Hyperuricaemia is common in preeclampsia. Its relationship and the utility in predicting of preeclampsia must be evaluated. The objective was to determine the association between maternal serum uric acid level and preeclampsia with or without severe features, including maternal and neonatal outcomes. A retrospective study was conducted at Rajavithi Hospital between June 2015 and May 2019. Inferential analysis comparison using binary logistic regression analysis and correlation using Chi-Square test/Fisher's exact test were used for analysis. Among the 400 participants, 331 (82.7%) women were preeclampsia with severe features. The mean uric acid level was significantly higher in women with preeclampsia with severe features compared to those without (6.44 ± 1.44 vs 5.87 ± 1.53 mg/dL, p-value = .016). Uric acid greater than 7 mg/dL was associated with renal involvement and preeclampsia with severe features. Uric acid 5-7 and greater than 7 mg/dL correlated with preterm birth (OR 2.67, 95% CI 1.59-4.49 and OR 4.89, 95% CI 2.75-8.68, respectively). Uric acid greater than 7 mg/dL also increased the risk of RDS and NICU admission. In conclusion, a high uric acid level is associated with preeclampsia with severe features and adverse pregnancy outcomes and may be the predictor of the severity of preeclampsia.Impact statementWhat is already known on this subject? Hyperuricaemia is a common finding in preeclamptic pregnancy due to reduction of uric acid clearance secondary to reduced glomerular filtration rate, increased reabsorption, and decreased secretion. The correlation of increase maternal uric acid level and preeclampsia including adverse pregnancy outcomes has been evaluated and supported the use of uric acid as a predictor for preeclampsia development. However, its clinical utility is still debateable.What the results of this study add? The present study demonstrated the association between higher maternal serum uric acid level and severity of preeclampsia. Particularly, serum uric acid greater than 7 mg/dL was associated with preeclampsia with severe features. Additionally, serum uric acid level 5-7 mg/dL and greater than 7 mg/dL had a positive correlation with adverse maternal and neonatal outcomes.What the implications are of these findings for clinical practice and/or further research? Maternal serum uric acid may be used as the predictor of severity of preeclampsia. However, the sensitivity and specificity and the precise clinical utility of uric acid related to preeclampsia need to be further evaluated in larger sample size.

Role of Salivary Uric Acid Versus Serum Uric Acid in Predicting Maternal Complications of Pre-Eclampsia in a Rural Hospital in Central India: A Two-Year, Cross-Sectional Study

Background

Hypertensive disorders during pregnancy are an important topic of concern, specifically in rural and remote areas of India where there is a lack of awareness and it is difficult to maintain proper follow-up of pregnant females to screen them for complications developed during pregnancy. Gestational hypertension and pre-eclampsia result in the abruption of the placenta, hemolysis, elevated liver enzymes, low platelet count syndrome, eclampsia, and disseminated intravascular coagulation, which can be a serious threat to the health of the mother and the fetus. Therefore, it is important to identify biomarkers for diagnosing and predicting the complications of pre-eclampsia that may aid the obstetric high-dependency units based in rural areas to tackle this important health hazard during pregnancy.

Methodology

A total of 180 singleton pregnant women of more than 34 weeks of gestational age were enrolled in this study. All women were divided into three groups (control group, severe pre-eclampsia, and non-severe pre-eclampsia) based on the severity of blood pressure and the presence of proteinuria (≥+1 by the dipstick method). Salivary and serum uric acid levels were measured through morning samples, and all patients were monitored for the development of complications and outcomes. Salivary uric acid and serum uric acid levels were correlated with each other and with maternal complications of pre-eclampsia.

Results

Mean salivary uric acid (mg/dL) in severe pre-eclampsia was (6.72 ± 0.49) significantly higher compared to non-severe pre-eclampsia (4.75 ± 0.94) and control (3.13 ± 0.43). Mean serum uric acid (mg/dL) in severe pre-eclampsia was (8.13 ± 0.87) significantly higher compared to non-severe pre-eclampsia (6.23 ± 0.76) and control (3.85 ± 0.46).The lowest best cut-off value of maternal salivary uric acid was 5.06 mg/dL, above which one can predict maternal complications with a diagnostic accuracy of 78.33%.

Conclusions

Salivary uric acid and serum uric acid levels are significantly raised in cases of pre-eclampsia in comparison to normal pregnancy. Salivary uric acid and serum uric acid are correlated significantly indicating that salivary uric acid can function as a cost-effective, novel marker to provide an idea about serum uric acid levels. The prognostic accuracy of salivary uric acid was good in predicting maternal complications among cases of pre-eclampsia (severe and non-servere) and early-onset maternal complications. Therefore, it may be utilized as a helpful marker to identify high-risk patients.

Serum Uric Acid Level as a Predictive Biomarker of Gestational Hypertension Severity; A Prospective Observational Case-Control Study

BACKGROUND

Pre-eclampsia poses a significant potential risk of hypertensive disorders during pregnancy, a leading cause of maternal deaths. Hyperuricemia is associated with adverse effects on endothelial function, normal cellular metabolism, and platelet aggregation and adhesion. This study was designed to compare serum urate levels in normotensive pregnant women to those with pregnancy-induced hypertension, and to evaluate its value as a potential predictive marker of hypertension severity during pregnancy.

METHODS

A prospective, observational, case-control study conducted on 100 pregnant women in their third trimester. Pregnant women were classified into two groups (n=50) according to arterial blood pressure measurements: group I had normal blood pressure, and group II had a blood pressure of ≥ 140/90, which was further subdivided according to hypertension severity into IIa (pregnancy- induced hypertension, IIb (mild pre-eclampsia), and IIc (severe pre-eclampsia). Blood samples were obtained on admission. Serum urate, high sensitive C-reactive protein, and interleukin-1β levels, and lipid profile were compared among the groups.

RESULTS

A significant increase in the mean values of serum urate, C-reactive protein, and interleukin- 1β levels was detected in gestational hypertensives. In addition, there was a positive correlation between serum urate levels and C-reactive protein and interleukin-1β, as well as between serum urate levels and hypertension severity.

CONCLUSION

Hyperuricemia and increased C-reactive protein and interleukin-1β serum levels correlate with the severity of pregnancy-induced hypertension, and these biomarkers may play a role in the pathogenesis of pre-eclampsia. Serum urate measurement is sensitive, reliable markers that correlate well with the severity of hypertension in pregnant females with pre-eclampsia.