Validation of hospital discharge diagnoses for hypertensive disorders of pregnancy

Cardiovascular Data Quality in the Danish National Patient Registry (1977-2024): A Systematic Review

Background

The increasing use of routinely collected health data for research puts great demands on data quality. The Danish National Patient Registry (DNPR) is renowned for its longitudinal data registration since 1977 and is a commonly used data source for cardiovascular epidemiology.

Objective

To provide an overview and examine determinants of the cardiovascular data quality in the DNPR.

Methods

We performed a systematic literature search of MEDLINE (PubMed) and the Danish Medical Journal, and identified papers validating cardiovascular variables in the DNPR during 1977-2024. We also included papers from reference lists, citations, journal e-mail notifications, and colleagues. Measures of data quality included the positive predictive value (PPV), negative predictive value, sensitivity, and specificity.

Results

We screened 2,049 papers to identify 63 relevant papers, including a total of 229 cardiovascular variables. Of these, 200 variables assessed diagnoses, 24 assessed treatments (10 surgeries and 14 other treatments), and 5 assessed examinations. The data quality varied substantially between variables. Overall, the PPV was ≥90% for 36% of variables, 80-89% for 26%, 70-79% for 16%, 60-69% for 7%, 50-59% for 4%, and <50% for 11% of variables. The predictive value was generally higher for treatments (PPV≥95% for 92%) and examinations (PPV≥95% for 100%) than for diagnoses (PPV≥80% for 71%). Moreover, the PPV varied for individual diagnoses depending on the algorithm used to identify them. Key determinants for validity were patient contact type (inpatient vs outpatient), diagnosis type (primary vs secondary), setting (university vs regional hospitals), and calendar year.

Conclusion

The validity of cardiovascular variables in the DNPR is high for treatments and examinations but varies considerably between individual diagnoses depending on the algorithm used to define them.

Validation of the Finnish Care register for Health Care diagnoses for preeclampsia, gestational diabetes and preterm delivery

BACKGROUND

Centrally collected Finnish national health register data on adverse pregnancy outcomes are available for research, but the validity of the data is largely unknown. Our aim was to compare the diagnoses of preeclampsia (PE), gestational diabetes (GDM), and preterm delivery from hospital records with the registry based diagnoses from the Finnish Care Register for Health Care (FCR). Data on gestational age at delivery from the Medical Birth Registry (MBR) was also studied.

METHODS

The Finnish Genetics of Pre-eclampsia Consortium (FINNPEC) Study cohort was used as a data source. Each diagnosis was ascertained from electronic hospital records. The validity of diagnoses obtained by record linkage of FCR and MBR was assessed against the classification previously confirmed independently by a research nurse and a study physician.

RESULTS

Sensitivity of PE diagnoses in FCR was 80.3 % (95 % CI 78.3 % to 82.2 %) andspecificity 95.3 % (95 % CI 93.9 % to 96.4 %). Sensitivity for GDM was 64.1 % (95 % CI: 58.7 % - 69.3 %) and specificity 98.5 % (95 % CI: 97.9 % - 98.9 %), whereas sensitivity and specificity for preterm delivery were 32.4 % (95 % CI: 29.0 % - 36.0 %) and 99.7 % (95 % CI: 99.3 % - 99.9 %). Sensitivity of preterm delivery in the MBR was 99.1 % and specificity 99.9 %.

CONCLUSIONS

FCR registry diagnoses for PE have satisfactory sensitivity and high specificity. Diagnoses for GDM and preterm delivery have lower sensitivity limiting their use in studies, and data from MBR should be preferred when studying preterm deliveries.

Validation of Obstetric Diagnosis and Procedure Codes in the Danish National Patient Registry in 2017

Purpose

This study aimed to systematically evaluate the validity of variables related to pregnancy, delivery, and key characteristics of the infant in the Danish National Patient Register using maternal medical records as the reference standard.

Patients and Methods

We reviewed medical records of 1264 women giving birth in the Region of Southern Denmark during 2017. We calculated positive (PPV) and negative (NPV) predictive values, sensitivity, and specificity to estimate the validity of 49 selected variables.

Results

The PPV was ≥0.90 on most pregnancy-related variables including parity, pre-gestational BMI, diabetes disorders, and previous cesarean section, while it was lower for hypertensive disorders, especially mild to moderate preeclampsia (0.49, 95% CI 0.32-0.66). Sensitivity ranged from 0.80 to 1.00 on all pregnancy-related variables, except hypertensive disorders (sensitivity 0.38-0.71, lowest for severe preeclampsia). On most delivery-related variables including obstetric surgical procedures (eg cesarean section and induction of labor), pharmacological pain-relief, and gestational age at delivery, PPV's ranged from 0.98 to 1.00 and the corresponding sensitivities from 0.87 to 1.00. Regarding infant-related variables, both the APGAR score registered five minutes after delivery and birthweight yielded a PPV of 1.00.

Conclusion

Obstetric coding in the Danish National Patient Register shows very high validity and completeness making it a valuable source for epidemiologic research.

High-Sensitivity Cardiac Troponin I Enhances Preeclampsia Prediction Beyond Maternal Factors and the sFlt-1/PlGF Ratio

BACKGROUND

Preeclampsia shares numerous risk factors with cardiovascular diseases. Here, we aimed to assess the potential utility of high-sensitivity cardiac troponin I (hs-cTnI) values during pregnancy in predicting preeclampsia occurrence.

METHODS

This study measured hs-cTnI levels in 3721 blood samples of 2245 pregnant women from 4 international, prospective cohorts. Three analytical approaches were used: (1) a cross-sectional analysis of all women using a single blood sample, (2) a longitudinal analysis of hs-cTnI trajectories in women with multiple samples, and (3) analyses of prediction models incorporating hs-cTnI, maternal factors, and the sFlt-1 (soluble fms-like tyrosine kinase 1)/PlGF (placental growth factor) ratio.

RESULTS

Women with hs-cTnI levels in the upper quarter had higher odds ratios for preeclampsia occurrence compared with women with levels in the lower quarter. Associations were driven by preterm preeclampsia (odds ratio, 5.78 [95% CI, 2.73-12.26]) and remained significant when using hs-cTnI as a continuous variable adjusted for confounders. Between-trimester hs-cTnI trajectories were independent of subsequent preeclampsia occurrence. A prediction model incorporating a practical hs-cTnI level of detection cutoff (≥1.9 pg/mL) alongside maternal factors provided comparable performance with the sFlt-1/PlGF ratio. A comprehensive model including sFlt-1/PlGF, maternal factors, and hs-cTnI provided added value (cross-validated area under the receiver operator characteristic, 0.78 [95% CI, 0.73-0.82]) above the sFlt-1/PlGF ratio alone (cross-validated area under the receiver operator characteristic, 0.70 [95% CI, 0.65-0.76]; P=0.027). As assessed by likelihood ratio tests, the addition of hs-cTnI to each prediction model significantly improved the respective prediction model not incorporating hs-cTnI, particularly for preterm preeclampsia. Net reclassification improvement analyses indicated that incorporating hs-cTnI improved risk prediction predominantly by correctly reclassifying women with subsequent preeclampsia occurrence.

CONCLUSIONS

These exploratory findings uncover a potential role for hs-cTnI as a complementary biomarker in the prediction of preeclampsia. After validation in prospective studies, hs-cTnI, alongside maternal factors, may either be considered as a substitute for angiogenic biomarkers in health care systems where they are sparce or unavailable, or as an enhancement to established prediction models using angiogenic markers.

Combined Impact of Migraine and Pregnancy-Induced Hypertension on Long-term Risk of Premature Myocardial Infarction and Stroke

BACKGROUND AND OBJECTIVES

Migraine and pregnancy-induced hypertension (PIH) are known to increase cardiovascular risk on their own. However, evidence is limited on the combined impact of migraine and PIH on risk of cardiovascular disease. The aim of this study was to examine the combined impact of migraine and PIH on risk of premature (age 60 years and younger) major adverse cardiovascular and cerebrovascular events (MACCE), a composite end point consisting of myocardial infarction, stroke, or death due to one of these diseases.

METHODS

We conducted a population-based cohort study in Denmark (1996-2018) among women who had delivered at least one child. This population was stratified into 4 cohorts: women with neither migraine nor PIH, women with migraine, women with PIH, and women with both migraine and PIH. As a measure of absolute risk, we computed the 20-year cumulative incidence of premature MACCE, treating death by other causes than myocardial infarction and stroke as a competing risk. We used Cox regression to compute 20-year adjusted hazard ratios (HRs) of premature MACCE. Women with neither migraine nor PIH served as the comparison cohort.

RESULTS

The 20-year absolute risk of premature MACCE was 1.3% (95% CI 1.2%; 1.3%) for women without migraine and without PIH (n = 1,288,541), 2.2% (95% CI 2.0%; 2.4%) for women with migraine (n = 54,827), 2.8% (95% CI 2.6%; 3.1%) for women with PIH (n = 49,008), and 3.1% (95% CI 2.1%; 4.4%) for women with both migraine and PIH (n = 3,140). The adjusted HR of premature MACCE was 1.66 (95% confidence interval [CI] 1.50-1.84) for women with migraine, 2.76 (95% CI 2.52-3.03) for women with PIH, and 2.41 (95% CI 1.61-3.61) for women with both migraine and PIH.

DISCUSSION

Migraine and PIH separately increased the risk of premature MACCE. The risk of premature MACCE among women who had both migraine and PIH was similar to that among women with PIH only.

Systematic review of validated case definitions to identify hypertensive disorders of pregnancy in administrative healthcare databases

BACKGROUND

Administrative data are frequently used to study cardiovascular disease (CVD) risk in women with hypertensive disorders of pregnancy (HDP). Little is known about the validity of case-finding definitions (CFDs, eg, disease classification codes/algorithms) designed to identify HDP in administrative databases.

METHODS

A systematic review of the literature. We searched MEDLINE, Embase, CINAHL, Web of Science and grey literature sources for eligible studies. Two independent reviewers screened articles for eligibility and extracted data. Quality of reporting was assessed using checklists; risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool, adapted for administrative studies. Findings were summarised descriptively.

RESULTS

Twenty-six studies were included; most (62%) validated CFDs for a variety of maternal and/or neonatal outcomes. Six studies (24%) reported reference standard definitions for all HDP definitions validated; seven reported all 2×2 table values for ≥1 CFD or they were calculable. Most CFDs (n=83; 58%) identified HDP with high specificity (ie, ≥98%); however, sensitivity varied widely (3%-100%). CFDs validated for any maternal hypertensive disorder had the highest median sensitivity (91%, range: 15%-97%). Quality of reporting was generally poor, and all studies were at unclear or high risk of bias on ≥1 QUADAS-2 domain.

CONCLUSIONS

Even validated CFDs are subject to bias. Researchers should choose the CFD(s) that best align with their research objective, while considering the relative importance of high sensitivity, specificity, negative predictive value and/or positive predictive value, and important characteristics of the validation studies from which they were derived (eg, study prevalence of HDP, spectrum of disease studied, methodological rigour, quality of reporting and risk of bias). Higher quality validation studies on this topic are urgently needed.

PROSPERO REGISTRATION NUMBER

CRD42021239113.

Elevated blood pressure in pregnant women with gestational diabetes according to the WHO criteria: importance of overweight

OBJECTIVE

Hypertension before and during early pregnancy has been associated with an increased risk of gestational diabetes mellitus (GDM) in retrospective analyses. We aimed to investigate the prospective blood pressure trackings in a population-based cohort of pregnant women, who were stratified according to their metabolic status in early third trimester.

METHODS

We recorded blood pressure longitudinally during pregnancy in 1230 women from the Odense Child Cohort, Denmark. Fasting glucose and insulin were measured at gestational weeks 28-30. Metabolic status was evaluated according to the WHO 2013 threshold for GDM (GDM-WHO: fasting plasma glucose ≥5.1 mmol/l), insulin and homeostatic model assessment of insulin resistance (HOMA-IR). Relationships between metabolic status in third trimester and blood pressure trajectories were evaluated with adjusted linear mixed models. Trajectory was defined as blood pressure records in pregnancy per 4 weeks interval.

RESULTS

Prevalence of GDM-WHO was 40% (498/1230). GDM-WHO was associated with 1.46 (0.22-2.70) mmHg higher SBP and 1.04 (0.07-2.01) mmHg higher DBP trajectories in the overall cohort. The associations were driven by differences in the overweight group, with 3.14 (1.05-5.25) mmHg higher SBP and 1.94 (0.42-3.47) mmHg higher DBP per 4 weeks in women with GDM-WHO compared with women without GDM-WHO. GDM-WHO was not associated with blood pressure in women with normal weight. Blood pressure trajectories were elevated across quartiles of insulin resistance.

CONCLUSION

GDM-WHO is associated with higher blood pressure in pregnancy, and there appears to be a stronger effect in overweight women.

Validation of Hypertensive Disorders During Pregnancy: ICD-10 Codes in a High-burden Southeastern United States Hospital

BACKGROUND

Identification of hypertensive disorders in pregnancy research often uses hospital International Classification of Diseases v. 10 (ICD-10) codes meant for billing purposes, which may introduce misclassification error relative to medical records. We estimated the validity of ICD-10 codes for hypertensive disorders during pregnancy overall and by subdiagnosis, compared with medical record diagnosis, in a Southeastern United States high disease burden hospital.

METHODS

We linked medical record data with hospital discharge records for deliveries between 1 July 2016, and 30 June 2018, in an Atlanta, Georgia, public hospital. For any hypertensive disorder (with and without unspecified codes) and each subdiagnosis (hemolysis, elevated liver enzymes, and low platelet count [HELLP] syndrome, eclampsia, preeclampsia with and without severe features, chronic hypertension, superimposed preeclampsia, and gestational hypertension), we calculated positive predictive value (PPV), negative predictive value (NPV) sensitivity, and specificity for ICD-10 codes compared with medical record diagnoses (gold standard).

RESULTS

Thirty-seven percent of 3,654 eligible pregnancies had a clinical diagnosis of any hypertensive disorder during pregnancy. Overall, ICD-10 codes identified medical record diagnoses well (PPV, NPV, specificity >90%; sensitivity >80%). PPV, NPV, and specificity were high for all subindicators (>80%). Sensitivity estimates were high for superimposed preeclampsia, chronic hypertension, and gestational hypertension (>80%); moderate for eclampsia (66.7%; 95% confidence interval [CI] = 22.3%, 95.7%), HELLP (75.0%; 95% CI = 50.9%, 91.3%), and preeclampsia with severe features (58.3%; 95% CI = 52.6%, 63.8%); and low for preeclampsia without severe features (3.2%; 95% CI, 1.4%, 6.2%).

CONCLUSIONS

We provide bias parameters for future US-based studies of hypertensive outcomes during pregnancy in high-burden populations using hospital ICD-10 codes.

Exposure to perfluoroalkyl substances and blood pressure in pregnancy among 1436 women from the Odense Child Cohort

BACKGROUND

Previous studies of association between exposure to poly- and perfluoroalkyl substances (PFAS) and gestational hypertension (GH) and preeclampsia (PE) have shown conflicting results, but most dichotomized outcome and did not study continuous blood pressure (BP) changes.

OBJECTIVES

To study the association between PFAS exposure in early pregnancy and maternal BP trajectories in pregnancy, gestational hypertension and preeclampsia.

METHODS

1436 women were enrolled in the Odense Child Cohort in early pregnancy and had a serum sample drawn, from which perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA) were measured using LC-MS/MS. Repeated BP measurements through pregnancy and information on PE were obtained from hospital files. Adjusted linear mixed models were used to investigate association between PFAS exposure and BP trajectory. Associations between PFAS and PE and GH were assessed by Cox proportional hazards model.

RESULTS

All women had measurable concentrations of PFAS. In all of many comparisons higher PFAS exposure (apart from PFHxS) was associated with higher systolic (SBP) and diastolic (DBP) blood pressures, although not all were significant, which is unlikely to be due to chance. After adjustment, each doubling in PFOS or PFOA exposure was associated with 0.47 mmHg (95% CI: -0.13; 1.08) and 0.36 mmHg (-0.19; 0.92) higher SBP; and 0.58 mmHg (0.13; 1.04) and 0.37 mmHg (-0.05; 0.79) higher DBP. No clear associations between PFAS exposure and PE or GH were found.

DISCUSSION

The magnitude of the association between PFAS exposure and BP might appear small, statistically non-significant and the possible clinical importance low. However, at a population level this may slightly shift the distribution of BP towards an increased incidence of GH. If BP increases in pregnancy, it may have long-term impact on health not only of the pregnant woman but also of her offspring.

Associations of thrombocytopenia, transaminase elevations, and transfusion with laboratory coagulation tests in women with preeclampsia: a cross-sectional study

BACKGROUND

Women with preeclampsia may develop coagulopathy, predisposing to bleeding complications. Although guidelines and prior studies conflict, we hypothesized that in preeclampsia, abnormal coagulation test results are more common in women with thrombocytopenia or transaminase elevations and increase the transfusion risk. Our objectives were to investigate: 1. patterns of coagulation testing; 2. relationships between platelet count, transaminase level, and the risk of abnormal coagulation tests; 3. risk of bleeding complications; and 4. characteristics of patients with markedly abnormal coagulation parameters.

METHODS

We conducted a cross-sectional study of deliveries of women with preeclampsia who had undergone activated partial thromboplastin time (aPTT) or international normalized ratio (INR) testing at one of two hospitals between 1994 and 2018.

RESULTS

Of 10 699 women with preeclampsia, 3359 (32.7%) had coagulation testing performed and aPTT or INR elevations were present in 124 (3.7 %). Coagulation abnormalities were more common in women with thrombocytopenia or transaminase elevations (n=82) compared with those without (n=42) (6.7%, 95% CI 5.5 to 8.2 vs 1.8%, 95% CI 1.3 to 2.5). Transfusion was more common among women with abnormal coagulation parameters (n=124) compared with those without (n=39) (33.1 vs 7.0%, P <0.001). Among 26 patients with an aPTT ≥40 s or an INR ≥1.4, six required transfusion (all had placental abruption and disseminated intravascular coagulopathy).

CONCLUSIONS

Coagulation testing was inconsistently performed in this cohort. Platelet counts and transaminase levels inadequately detected abnormal coagulation test results. Abnormal coagulation test results were associated with a markedly higher risk for red blood cell transfusion.

Reporting of gestational diabetes and other maternal medical conditions: validation of routinely collected hospital data from New South Wales, Australia

Introduction

Hospital datasets are a valuable resource for examining prevalence and outcomes of medical conditions during pregnancy. To enable effective research and health planning, it is important to determine whether variables are reliably captured.

Objective

To examine the reliability of reporting of gestational and pre-existing diabetes, hypertension, thyroid conditions, and morbid obesity in coded hospital records that inform the population-level New South Wales Admitted Patient Data Collection.

Methods

Coded hospital admission data from two large tertiary hospitals in New South Wales, from 2011 to 2015, were compared with obstetric data, collected by midwives at outpatient pregnancy booking and in hospital after birth, as the reference standard. Records were deterministically linked and sensitivity, specificity, positive predictive values and negative predictive values for the conditions of interest were obtained.

Results

There were 36,051 births included in the analysis. Sensitivity was high for gestational diabetes (83.6%, 95% CI 82.4–84.7%), pre-existing diabetes (88.2%, 95% CI 84.1–91.6%), and gestational hypertension (80.1%, 95% CI 78.2–81.9%), moderate for chronic hypertension (53.5%, 95% CI 47.8–59.1%), and low for thyroid conditions (12.9%, 95% CI 11.7–14.2%) and morbid obesity (9.8%, 95% CI 7.6–12.4%). Specificity was high for all conditions (≥97.8%, 95% CI 97.7–98.0) and positive predictive value ranged from 53.2% for chronic hypertension (95% CI 47.5–58.8%) to 92.7% for gestational diabetes (95% CI 91.8–93.5%).

Conclusion

Our findings suggest that coded hospital data are a reliable source of information for gestational and pre-existing diabetes and gestational hypertension. Chronic hypertension is less consistently reported, which may be remedied by grouping hypertension types. Data on thyroid conditions and morbid obesity should be used with caution, and if possible, other sources of data for those conditions should be sought.

Blood Pressure and Angiogenic Markers in Pregnancy: Contributors to Pregnancy-Induced Hypertension and Offspring Cardiovascular Risk

Pregnancy-induced hypertension is a severe pregnancy complication, increasing risk of long-term cardiovascular disease in mothers and offspring. We hypothesized that maternal blood pressure in pregnancy associated with offspring blood pressure; that the associations were sex-specific; and that maternal circulating placental angiogenic markers (PlGF [placental growth factor] and sFlt-1 [soluble fms-like tyrosine kinase-1]) mediated this relationship. We analyzed data from 2434 women and 2217 children from the Odense Child Cohort, a prospective Danish cohort study. Offspring blood pressure trajectory from 4 months to 5 years was highly associated to maternal first, second, and third trimester blood pressure, and mean blood pressure in pregnancy, independent of maternal and offspring covariates. There were offspring sex-specific associations: Girls from mothers in the highest quartile of first and third trimester blood pressure had significantly higher systolic blood pressure at 5 years than the rest of the cohort (mean difference±SEM: 1.81±0.59 and 2.11±0.59 mm Hg, respectively, all P<0.01); whereas boys had significantly higher diastolic blood pressure at 5 years (mean difference±SEM: 1.11±0.45 and 1.03±0.45, respectively, all P<0.05). Concentrations of PlGF at gestational week 28 correlated inversely to maternal gestational blood pressure trajectory, independent of the diagnosis of pregnancy-induced hypertension, adjusted β coefficients (95% CI) for predicting systolic blood pressure (SBP): -3.18 (-4.66 to -1.70) mm Hg, for predicting diastolic blood pressure (DBP): -2.48 (-3.57 to -1.40) mm Hg. In conclusion, maternal gestational blood pressure predicted offspring blood pressure trajectory until 5 years in a sex-differential manner. Furthermore, subtle alterations in blood pressure in early pregnancy preceded hypertension or preeclampsia, and PlGF was a mediator of cardiovascular health in pregnancy.

Reduced coronary flow velocity reserve in women with previous pre-eclampsia: link to increased cardiovascular disease risk

OBJECTIVES

To evaluate differences in coronary microvascular function approximately 12 years after delivery between women who had had early- (EO-PE) or late- (LO-PE) onset pre-eclampsia and those who had had a normotensive pregnancy, and to assess the relationship between microvascular function and myocardial deformation at follow-up in these women.

METHODS

This was a case-control study of 88 women who had delivered at the Department of Gynecology and Obstetrics, Randers Regional Hospital, Randers, Denmark, between 1998 and 2008. Coronary flow velocity reserve (CFVR) was assessed by Doppler echocardiography approximately 12 years after delivery. Women were grouped according to whether the pregnancy had been complicated by EO-PE (n = 29) or LO-PE (n = 20), or had been normotensive (controls) (n = 39). Study groups were matched for maternal age and time since delivery. CFVR at follow-up was compared between the study groups. Regression analysis was used to assess the association between gestational age at onset of PE and CFVR. The association between left ventricular global longitudinal strain (LV-GLS) and CFVR at follow-up was also evaluated.

RESULTS

Resting coronary flow velocity assessed 12 years after delivery was comparable between the study groups (P = 0.55), whereas peak hyperemic flow velocity was significantly lower in the EO-PE group than in the LO-PE group (P < 0.01) and controls (P < 0.0001). As such, mean CFVR at follow-up was significantly lower in the EO-PE group than in the LO-PE group (P < 0.01) and controls (P < 0.0001). CFVR was < 2.5 in 48% of women in the EO-PE group, 25% of those in the LO-PE group and 8% of controls (P < 0.01). There was a significant positive association between gestational age at diagnosis of PE and CFVR at 12-year follow-up (β1 = 1.8 (95% CI, 0.8-2.9); P < 0.01). This relationship remained significant after adjustment for cardiovascular risk factors, namely mean arterial blood pressure, glycated hemoglobin level, body mass index, low-density lipoprotein cholesterol level and smoking status (P < 0.05). There was a significant association between LV-GLS and CFVR in women who had had PE (β1 = -1.5 (95% CI, -2.2 to -0.9); R²  = 0.33, P < 0.0001).

CONCLUSIONS

Low gestational age at onset of PE, both as a continuous variable and when categorized as early onset, was associated with decreased CFVR 12 years after delivery. Nearly 50% of women who had had EO-PE had CFVR < 2.5 at follow-up. Reduced CFVR in women who had had PE was associated with subclinical myocardial dysfunction in terms of reduced LV-GLS. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Normal-range urinary albumin excretion associates with blood pressure and renal electrolyte handling in pregnancy

Albuminuria in the pathological range is a significant predictor of preeclampsia. In healthy persons, high normal urinary albumin predicts a later incidence of hypertension and is associated with salt sensitivity of blood pressure. We hypothesized that in pregnancy urinary albumin in the normal range associates with blood pressure through activation of distal Na⁺ reabsorption and renal salt retention by plasma factors cofiltered with albumin. We analyzed 24-h urine collections and plasma samples from gestational week 29 of 560 pregnant women from the Odense Child Cohort, a Danish population-based cohort. Plasma and urinary aldosterone were measured by ELISA. Plasma and urinary Na⁺, K⁺, Cl^-, and creatinine were also determined. Predictive values of urinary albumin were assessed by linear mixed, multiple, and Cox regression analyses. Primary outcomes were blood pressure and renal electrolyte handling. Twenty-four-hour urinary albumin excretion at gestational week 29 associated with gestational blood pressure trajectory, with adjusted β coefficients (95% confidence intervals) for each 10-fold increase in urinary albumin as follows: 5.71 (1.60 to 9.81) mmHg for systolic blood pressure and 4.39 (1.41 to 7.38) mmHg for diastolic blood pressure. Urinary albumin was inversely associated with fractional excretion rates of Na⁺, K⁺, and Cl^-, with adjusted β coefficients (95% confidence intervals) for each 10-fold increase in urine albumin as follows: -0.25 (-0.35 to -0.14), -5.06 (-6.81 to -3.30), and -0.28 (-0.41 to -0.15), respectively. In conclusion, at gestational week 29, urinary albumin excretion in the normal range associated with blood pressure and renal electrolyte handling independent of potential confounders.

Aldosterone, Salt, and Potassium Intakes as Predictors of Pregnancy Outcome, Including Preeclampsia

The mineralocorticoid aldosterone increases in plasma in healthy pregnancy along with renin and angiotensin II and plays a key role in the physiological plasma volume expansion. In mice, aldosterone contributes to an optimal fetal development by enhancing PlGF (placental growth factor) expression and trophoblast cell proliferation. In preeclampsia, there is coincident suppression of aldosterone and impaired placental development. We hypothesized that aldosterone independently contributes to placental and birth weight in humans, and high dietary sodium and low potassium intakes affect this relationship adversely. We analyzed 24-hour urine collections and plasma samples from gestational week 29 in a subsample of 569 pregnant women from the Odense Child Cohort-a Danish population-based longitudinal cohort study. Plasma and urinary aldosterone were measured by ELISA, sodium and potassium excretions by flame photometer. Predictive values of aldosterone levels and sodium and potassium intakes were assessed by multiple and Cox regression analyses. Primary outcomes were placental weight and birth weight. Secondary outcome was preeclampsia. Urinary aldosterone excretion at gestational week 29 independently contributed to placental and birth weights (adjusted β-coefficients [95% CI], 24.50 [9.66-39.35] and 9.59 [4.57-14.61], respectively). Aldosterone levels were not associated to preeclampsia incidence. Salt intake >6 g/d was associated with development of preeclampsia (hazard ratio [95% CI], 5.68 [1.51-21.36]). At gestational week 29, urinary aldosterone excretion is an independent predictor of placental and birth weights. High salt intake is a risk factor for preeclampsia. In perspective, suppression of aldosterone in pregnancy has adverse trophic effects.

Prediction of birth weight small for gestational age with and without preeclampsia by angiogenic markers: an Odense Child Cohort study

Purpose: To investigate the predictive performance of placental growth factor (PlGF) and soluble FMS-like kinase 1 (sFlt-1) on birth weight and small for gestational age (SGA), in a large, population-based cohort.Methods: Women enrolled in the population-based, prospective Odense Child Cohort Study with early (GA < 20 weeks) and/or late (≥20 weeks) pregnancy blood samples (n = 1937) were included. The association between log-transformed values of the biomarkers and birth weight Z-score was studied using multivariate regression models. The prediction of SGA overall, and in women developing preeclampsia, by biomarkers was evaluated using receiver operating characteristic analyses.Results: No substantial associations between early pregnancy biomarkers and SGA were seen. PlGF measured in late pregnancy demonstrated the strongest association with birth weight Z-score (adjusted β-coefficient = 0.43 [95%CI = 0.35; 0.50]). The area under curve (AUC) for predicting SGA was higher for sFlt-1/PlGF compared to sFlt-1 (0.74 versus 0.63, p = .006) and reached excellent prediction for SGA after preeclampsia (AUC 0.94). Optimal sFlt-1/PlGF ratio cut-offs had higher negative predictive value (NPV) and positive predictive value (PPV) for SGA (cut-off > 5.0; NPV = 99.1%, PPV = 5.4%) compared to each marker individually.Conclusion: The sFlt-1/PlGF ratio is a potential predictor of SGA in population-based screening, particularly when preeclampsia is also present.

The Reliability of Electronic Health Record Data Used for Obstetrical Research

BACKGROUND

Hospital electronic health record (EHR) data are increasingly being called upon for research purposes, yet only recently has it been tested to examine its reliability. Studies that have examined reliability of EHR data for research purposes have varied widely in methods used and field of inquiry, with little reporting of the reliability of perinatal and obstetric variables in the current literature.

OBJECTIVE

To assess the reliability of data extracted from a commercially available inpatient EHR as compared with manually abstracted data for common attributes used in obstetrical research.

METHODS

Data extracted through automated EHR reports for 3,250 women who delivered a live infant at a large hospital in the Pacific Northwest were compared with manual chart abstraction for the following perinatal measures: delivery method, labor induction, labor augmentation, cervical ripening, vertex presentation, and postpartum hemorrhage.

RESULTS

Almost perfect agreement was observed for all four modes of delivery (vacuum assisted: kappa = 0.92; 95% confidence interval [CI] = 0.88-0.95, forceps assisted: kappa = 0.90; 95%CI = 0.76-1.00, cesarean delivery: kappa = 0.91; 95%CI = 0.90-0.93, and spontaneous vaginal delivery: kappa = 0.91; 95%CI = 0.90-0.93). Cervical ripening demonstrated substantial agreement (kappa = 0.77; 95%CI = 0.73-0.80); labor induction (kappa = 0.65; 95%CI = 0.62-0.68) and augmentation (kappa = 0.54; 95%CI = 0.49-0.58) demonstrated moderate agreement between the two data sources. Vertex presentation (kappa = 0.35; 95%CI = 0.31-0.40) and post-partum hemorrhage (kappa = 0.21; 95%CI = 0.13-0.28) demonstrated fair agreement.

CONCLUSION

Our study demonstrates variability in the reliability of obstetrical data collected and reported through the EHR. While delivery method was satisfactorily reliable in our sample, other examined perinatal measures were less so when compared with manual chart abstraction. The use of multiple modalities for assessing reliability presents a more consistent and rigorous approach for assessing reliability of data from EHR systems and underscores the importance of requiring validation of automated EHR data for research purposes.

FLT1 and transcriptome-wide polyadenylation site (PAS) analysis in preeclampsia

Maternal symptoms of preeclampsia (PE) are primarily driven by excess anti-angiogenic factors originating from the placenta. Chief among these are soluble Flt1 proteins (sFlt1s) produced from alternatively polyadenylated mRNA isoforms. Here we used polyadenylation site sequencing (PAS-Seq) of RNA from normal and PE human placentae to interrogate transcriptome-wide gene expression and alternative polyadenylation signatures associated with early-onset PE (EO-PE; symptom onset < 34 weeks) and late-onset PE (LO-PE; symptom onset > 34 weeks) cohorts. While we observed no general shift in alternative polyadenylation associated with PE, the EO-PE and LO-PE cohorts do exhibit gene expression profiles distinct from both each other and from normal placentae. The only two genes upregulated across all transcriptome-wide PE analyses to date (microarray, RNA-Seq and PAS-Seq) are NRIP1 (RIP140), a transcriptional co-regulator linked to metabolic syndromes associated with obesity, and Flt1. Consistent with sFlt1 overproduction being a significant driver of clinical symptoms, placental Flt1 mRNA levels strongly correlate with maternal blood pressure. For Flt1, just three mRNA isoforms account for > 94% of all transcripts, with increased transcription of the entire locus driving Flt1 upregulation in both EO-PE and LO-PE. These three isoforms thus represent potential targets for therapeutic RNA interference (RNAi) in both early and late presentations.