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RESEARCH QUESTION: Does a commercially available quantitative beta-human chorionic gonadotrophin (BHCG) point of care testing (POCT) device improve workflow management in early pregnancy by performing comparably to gold standard laboratory methods, and is the performance of a validated pregnancy of unknown location (PUL) triage strategy maintained using POCT BHCG results? DESIGN: Women classified with a PUL between 2018 and 2021 at three early pregnancy units were included. The linear relationship of untreated whole-blood POCT and serum laboratory BHCG values was defined using coefficients and regression. Paired serial BHCG values were then incorporated into the validated M6 multinomial logistic regression model to stratify the PUL as at high risk or at low risk of clinical complications. The sensitivity and negative predictive value were assessed. The timings required for equivocal POCT and laboratory care pathways were compared. RESULTS: A total of 462 PUL were included. The discrepancy between 571 laboratory and POCT BHCG values was -5.2% (-6.2 IU/l), with a correlation coefficient of 0.96. The 133 PUL with paired 0 and 48 h BHCG values were compared using the M6 model. The sensitivity for high-risk outcomes (96.2%) and negative predictive values (98.5%) was excellent for both. Sample receipt and laboratory processing took 135 min (421 timings), compared with 12 min (91 timings) when using POCT (P < 0.0001). CONCLUSIONS: POCT BHCG values correlated well with laboratory testing measurements. The M6 model retained its performance when using POCT BHCG values. Using the model with POCT may improve workflow and patient care without compromising on effective PUL triage.
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Gravidez Ectópica , Gravidez , Humanos , Feminino , Gonadotropina Coriônica , Gonadotropina Coriônica Humana Subunidade beta , Valor Preditivo dos Testes , Modelos LogísticosRESUMO
OBJECTIVES: Quantitative human chorionic gonadotropin (hCG) measurements are used to manage women classified with a pregnancy of unknown location (PUL). Two point of care testing (POCT) devices that quantify hCG are commercially available. We verified the i-STAT 1 (Abbott) and the AQT 90 FLEX (Radiometer) prior to use in PUL triage. METHODS: Tests for precision, external quality assurance (EQA), correlation, hook effect and recovery were undertaken alongside a POCT usability assessment during this prospective multi-center verification. RESULTS: Coefficients of variation ranged between 4.0 and 5.1â¯% for the three i-STAT 1 internal quality control (IQC) solutions and between 6.8 and 7.3â¯% for the two AQT IQC solutions. Symmetric differences in POCT EQA results when compared with laboratory and EQA stock values ranged between 3.2 and 24.5â¯% for the i-STAT 1 and between 3.3 and 36.9â¯% for the AQT. Correlation coefficients (i-STAT 1: 0.96, AQT: 0.99) and goodness of fit curves (i-STAT 1: 0.92, AQT: 0.99) were excellent when using suitable whole blood samples. An hCG hook effect was noted with the i-STAT 1 between 572,194 and 799,089â¯IU/L, lower than the hook effect noted with the AQT, which was between 799,089 and 1,619,309â¯IU/L. When hematocrit concentration was considered in sample types validated for use with each device, hCG recovery was 108â¯% with the i-STAT 1 and 98â¯% with the AQT. The i-STAT 1 scored lower on usability overall (90/130) than the AQT (121/130, p<0.001, Mann-Whitney). CONCLUSIONS: Both hCG POCT devices were verified for use in clinical practice. Practical factors must also be considered when choosing which device to use in each unit.
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Sistemas Automatizados de Assistência Junto ao Leito , Interface Usuário-Computador , Gravidez , Humanos , Feminino , Estudos Prospectivos , Gonadotropina Coriônica , Testes ImediatosRESUMO
INTRODUCTION: There is no global agreement on how to best determine pregnancy of unknown location viability and location using biomarkers. Measurements of progesterone and ß human chorionic gonadotropin (ßhCG) are still used in clinical practice to exclude the possibility of a viable intrauterine pregnancy (VIUP). We evaluate the predictive value of progesterone, ßhCG, and ßhCG ratio cut-off levels to exclude a VIUP in women with a pregnancy of unknown location. MATERIAL AND METHODS: This was a secondary analysis of prospective multicenter study data of consecutive women with a pregnancy of unknown location between January 2015 and 2017 collected from dedicated early pregnancy assessment units of eight hospitals. Single progesterone and serial ßhCG measurements were taken. Women were followed up until final pregnancy outcome between 11 and 14 weeks of gestation was confirmed using transvaginal ultrasonography: (1) VIUP, (2) non-viable intrauterine pregnancy or failed pregnancy of unknown location, and (3) ectopic pregnancy or persisting pregnancy of unknown location. The predictive value of cut-off levels for ruling out VIUP were evaluated across a range of values likely to be encountered clinically for progesterone, ßhCG, and ßhCG ratio. RESULTS: Data from 2507 of 3272 (76.6%) women were suitable for analysis. All had data for ßhCG levels, 2248 (89.7%) had progesterone levels, and 1809 (72.2%) had ßhCG ratio. The likelihood of viability falls with the progesterone level. Although the median progesterone level associated with viability was 59 nmol/L, VIUP were identified with levels as low as 5 nmol/L. No single ßhCG cut-off reliably ruled out the presence of viability with certainty, even when the level was more than 3000 IU/L, there were 39/358 (11%) women who had a VIUP. The probability of viability decreases with the ßhCG ratio. Although the median ßhCG ratio associated with viability was 2.26, VIUP were identified with ratios as low as 1.02. A progesterone level below 2 nmol/L and ßhCG ratio below 0.87 were unlikely to be associated with viability but were not definitive when considering multiple imputation. CONCLUSIONS: Cut-off levels for ßhCG, ßhCG ratio, and progesterone are not safe to be used clinically to exclude viability in early pregnancy. Although ßhCG ratio and progesterone have slightly better performance in comparison, single ßhCG used in this manner is highly unreliable.
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Gravidez Ectópica/diagnóstico , Diagnóstico Pré-Natal , Adulto , Gonadotropina Coriônica/metabolismo , Gonadotropina Coriônica Humana Subunidade beta/metabolismo , Estudos de Coortes , Feminino , Humanos , Londres , Valor Preditivo dos Testes , Gravidez , Gravidez Ectópica/sangue , Progesterona/metabolismo , Estudos Prospectivos , Medicina EstatalRESUMO
BACKGROUND: Early pregnancy losses are common, but their psychologic sequelae are often overlooked. Previous studies have established links between miscarriage and early symptoms of anxiety and depression. However, the incidence of posttraumatic stress symptoms and the psychologic response specifically to ectopic pregnancies have not been investigated. OBJECTIVE: The purpose of this study was to investigate levels of posttraumatic stress, depression, and anxiety in women in the 9 months after early pregnancy loss, with a focus on miscarriage and ectopic pregnancy. Morbidity at 1 month was compared with a control group in healthy pregnancy. STUDY DESIGN: This was a prospective cohort study. Consecutive women were recruited from the early pregnancy and antenatal clinics at 3 London hospitals and received emailed surveys that contained standardized psychologic assessments that included the Hospital Anxiety and Depression Scale and Posttraumatic stress Diagnostic Scale, at 1, 3, and 9 months after loss. Control subjects were assessed after a dating scan. We assessed the proportion of participants who met the screening criteria for posttraumatic stress and moderate/severe anxiety or depression. We used logistic regression to calculate adjusted odds ratios. RESULTS: Seven hundred thirty-seven of 1098 women (67%) with early pregnancy loss (including 537 miscarriages and 116 ectopic pregnancies) and 171 of 187 control subjects (91%) agreed to participate. Four hundred ninety-two of the women with losses (67%) completed the Hospital Anxiety and Depression Scale after 1 month; 426 women (58%) completed it after 3 months, and 338 women (46%) completed it after 9 months. Eighty-seven control subjects (51%) participated. Criteria for posttraumatic stress were met in 29% of women with early pregnancy loss after 1 month and in 18% after 9 months (odds ratio per month, 0.80; 95% confidence interval, 0.72-0.89). Moderate/severe anxiety was reported in 24% after 1 month and in 17% after 9 months (odds ratio per month, 0.69; 95% confidence interval, 0.50-0.94). Moderate/severe depression was reported in 11% of the women after 1 month and 6% of the women after 9 months (odds ratio per month, 0.87; 95% confidence interval, 0.53-1.44). After miscarriage, proportions after 9 months were 16% for posttraumatic stress, 17% for anxiety, and 5% for depression. Corresponding figures after ectopic pregnancy were 21%, 23%, and 11%, respectively. In contrast, among control women with viable pregnancies, 13% reported moderate-to-severe anxiety (odds ratio loss at 1 month vs controls: 2.14; 95% confidence interval, 1.14-4.36), and 2% reported moderate-to-severe depression (odds ratio loss at 1 month vs control subjects: 3.88; 95% confidence interval, 1.27-19.2). CONCLUSION: Women experience high levels of posttraumatic stress, anxiety, and depression after early pregnancy loss. Distress declines over time but remains at clinically important levels at 9 months.
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Aborto Espontâneo/psicologia , Ansiedade/epidemiologia , Depressão/epidemiologia , Gravidez Ectópica/psicologia , Transtornos de Estresse Pós-Traumáticos/epidemiologia , Adulto , Estudos de Casos e Controles , Feminino , Humanos , Incidência , Londres/epidemiologia , Pessoa de Meia-Idade , Período Pós-Parto , Gravidez , Estudos Prospectivos , Escalas de Graduação Psiquiátrica , Fatores de Tempo , Adulto JovemRESUMO
INTRODUCTION: Early prediction of pregnancies destined to miscarry will allow couples to prepare for this common but often unexpected eventuality, and clinicians to allocate finite resources. We aimed to develop a prediction model combining clinical, demographic, and sonographic data as a clinical tool to aid counselling about first trimester pregnancy outcome. MATERIAL AND METHODS: This is a prospective, observational cohort study conducted at Queen Charlotte's and Chelsea Hospital, UK from March 2014 to May 2019. Women with confirmed intrauterine pregnancies between 5 weeks and their dating scan (11-14 weeks) were recruited. Participants attended serial ultrasound scans in the first trimester and at each visit recorded symptoms of vaginal bleeding, pelvic pain, nausea and vomiting using validated scoring tools. Pregnancies were followed up until the dating scan (11-14 weeks). Univariate and multivariate analyses were performed to predict first trimester viability. A model was developed with multivariable logistic regression, variables limited by feature selection, and bootstrapping with multiple imputation was used for internal validation. RESULTS: 1403 women were recruited and after exclusions, data were available for 1105. 160 women (14.5 %) experienced first trimester miscarriage and 945 women (85.5 %) had viable pregnancies at 11-14 weeks' gestation. The average gestational age at the initial visit (calculated from the menstrual dates) was 7 + 1 weeks (+/-12.2 days). A multivariable logistic regression model was developed to predict first trimester viability and included the variables: mean gestational sac diameter, presence of fetal heart pulsations, difference in gestational age from last menstrual period and from mean sac diameter on ultrasonography, current folic acid usage and maternal age. The model demonstrated good performance (optimism-corrected area under curve (AUC) 0.84, 95 % CI 0.81-0.87; optimism-corrected calibration slope 0.969). CONCLUSION: We have developed and internally validated a model to predict first trimester viability with good accuracy prior to the 11-14 week dating scan, which now needs to be externally validated prior to clinical use.
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Aborto Espontâneo , Ultrassonografia Pré-Natal , Gravidez , Feminino , Humanos , Lactente , Primeiro Trimestre da Gravidez , Estudos de Coortes , Aborto Espontâneo/diagnóstico por imagem , Ultrassonografia , Idade GestacionalRESUMO
Multiple measurements of serum human chorionic gonadotropin (hCG) are used to predict the final pregnancy outcome for women with a pregnancy of unknown location (PUL) and monitor the management of ectopic pregnancy (EP). Urine-based testing would be more convenient and economical. This prospective cohort study involving 80 women assessed the degree of correlation between serum and urine hCG levels and whether urine hCG levels have the potential to impact clinical decision making in the management of women with a PUL. Paired urine and serum hCG measurements differed quite widely but were well correlated and the degree of correlation improved after creatinine correction. Although serial serum hCG measurements appear to be better for the overall prediction of pregnancy outcome in PUL (AUC 0.77-0.94 compared to corrected urine AUC 0.69-0.84), serial urine hCG measurements may have a role in identifying subtypes of low-risk PUL (AUC 0.83-0.84).
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Gravidez Ectópica , Gonadotropina Coriônica , Feminino , Humanos , Gravidez , Resultado da Gravidez , Gravidez Ectópica/diagnóstico , Estudos ProspectivosRESUMO
OBJECTIVES: To investigate prognostic factors for anxiety, depression and post-traumatic stress (PTS) symptoms 1 month after early pregnancy loss (EPL). DESIGN: A prospective cohort study. Consecutive women were recruited, and demographic and clinical data were collected. Surveys containing the Hospital Anxiety and Depression Scale (HADS) and Post-traumatic Stress Diagnostic Scale (PDS) were emailed 1 month after a loss. Univariable logistic regression was performed to link factors with caseness of anxiety, depression or PTS according to screening measures. SETTING: Early pregnancy units of three central London hospitals. PARTICIPANTS: 737/1116 eligible women with an EPL were recruited. 492 responded to HADS and 487 to PDS. PRIMARY AND SECONDARY OUTCOME MEASURES: Primary outcome is the area under the curve (AUC) to predict any psychological morbidity (defined as moderate/severe anxiety or depression, or meeting screening criteria for PTS) for each variable. Further outcomes are explained variation (R2) and p value for any morbidity, and AUC, explained variation, and p value for each morbidity separately. RESULTS: Women who had a past diagnosis of a psychiatric condition were more likely to meet criteria for anxiety, depression or PTS (75% for current diagnosis vs 55% for past vs 30% for no diagnosis; AUC 0.61; R2 8.4%; p<0.0001), as were those with previous pregnancy loss (48% vs 30%; AUC 0.59; R2 4.3%; p<0.0001). Most of the assessed factors did not demonstrate potential utility in predicting psychological distress, including gestational age, overnight admission, time taken for diagnosis, pre-existing children and the diagnosis itself (miscarriage vs ectopic vs other) (AUCs≤0.54; R2≤0.9%). CONCLUSIONS: Women with a history of mental health problems, or those with previous losses, may be at higher risk of psychological illness 1 month after pregnancy loss. However, prognostic ability was poor overall. All women should be considered at risk.
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Aborto Espontâneo , Transtornos de Estresse Pós-Traumáticos , Aborto Espontâneo/epidemiologia , Aborto Espontâneo/psicologia , Ansiedade/diagnóstico , Ansiedade/epidemiologia , Ansiedade/psicologia , Criança , Depressão/diagnóstico , Depressão/epidemiologia , Depressão/psicologia , Feminino , Humanos , Gravidez , Prognóstico , Estudos Prospectivos , Transtornos de Estresse Pós-Traumáticos/diagnóstico , Transtornos de Estresse Pós-Traumáticos/epidemiologia , Transtornos de Estresse Pós-Traumáticos/psicologia , Estresse PsicológicoRESUMO
BACKGROUND: Clinical models to predict first trimester viability are traditionally based on multivariable logistic regression (LR) which is not directly interpretable for non-statistical experts like physicians. Furthermore, LR requires complete datasets and pre-established variables specifications. In this study, we leveraged the internal non-linearity, feature selection and missing values handling mechanisms of machine learning algorithms, along with a post-hoc interpretability strategy, as potential advantages over LR for clinical modeling. METHODS: The dataset included 1154 patients with 2377 individual scans and was obtained from a prospective observational cohort study conducted at a hospital in London, UK, from March 2014 to May 2019. The data were split into a training (70%) and a test set (30%). Parsimonious and complete multivariable models were developed from two algorithms to predict first trimester viability at 11-14 weeks gestational age (GA): LR and light gradient boosted machine (LGBM). Missing values were handled by multiple imputation where appropriate. The SHapley Additive exPlanations (SHAP) framework was applied to derive individual explanations of the models. RESULTS: The parsimonious LGBM model had similar discriminative and calibration performance as the parsimonious LR (AUC 0.885 vs 0.860; calibration slope: 1.19 vs 1.18). The complete models did not outperform the parsimonious models. LGBM was robust to the presence of missing values and did not require multiple imputation unlike LR. Decision path plots and feature importance analysis revealed different algorithm behaviors despite similar predictive performance. The main driving variable from the LR model was the pre-specified interaction between fetal heart presence and mean sac diameter. The crown-rump length variable and a proxy variable reflecting the difference in GA between expected and observed GA were the two most important variables of LGBM. Finally, while variable interactions must be specified upfront with LR, several interactions were ranked by the SHAP framework among the most important features learned automatically by the LGBM algorithm. CONCLUSIONS: Gradient boosted algorithms performed similarly to carefully crafted LR models in terms of discrimination and calibration for first trimester viability prediction. By handling multi-collinearity, missing values, feature selection and variable interactions internally, the gradient boosted trees algorithm, combined with SHAP, offers a serious alternative to traditional LR models.
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Aprendizado de Máquina , Árvores , Humanos , Modelos Logísticos , Gravidez , Primeiro Trimestre da Gravidez , Estudos ProspectivosRESUMO
OBJECTIVES: To assess if there is any association between hyperemesis gravidarum (HG), psychological morbidity and infant bonding and to quantify any psychosocial consequences of HG. DESIGN: Two-point prospective case-control, multicentre survey study with antenatal and postnatal data collection. SETTING: Three London hospitals. PARTICIPANTS: Pregnant women at ≤12 completed weeks gestation recruited consecutively over 2 years. Women with HG were recruited at the time of admission; controls recruited from a low risk antenatal clinic. 106 women were recruited to the case group and 108 to the control. Response rates at antenatal data collection were 87% and 85% in the case and control groups, respectively. Postnatally, the response rate was 90% in both groups. PRIMARY AND SECONDARY OUTCOME MEASURES: Primary outcomes were psychological morbidity in the antenatal and postnatal periods, infant bonding in the postnatal period and psychosocial implications of HG. Secondary outcomes were the effects of severity and longevity of HG and assessment of correlation between Edinburgh Postnatal Depression Scale scores and maternal-to-infant bonding scores. RESULTS: Antenatally, 49% of cases had probable depression compared with 6% of controls (OR 14.4 (5.29 to 39.44)). Postnatally, 29% of cases had probable depression versus 7% of controls (OR 5.2 (1.65 to 17.21)). There was no direct association between HG and infant bonding. 53% of women in the HG group reported needing four or more weeks of sick leave compared with 2% in the control group (OR 60.5 (95% CI 8.4 to 2535.6)). CONCLUSIONS: Long-lasting psychological morbidity associated with HG was evident. Significantly more women in the case group sought help for mental health symptoms in the antenatal period, however very few were diagnosed with or treated for depression in pregnancy or referred to specialist perinatal mental health services. HG did not directly affect infant bonding. Women in the case group required long periods off work, highlighting the socioeconomic impact of HG.
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Hiperêmese Gravídica , Estudos de Casos e Controles , Feminino , Humanos , Hiperêmese Gravídica/epidemiologia , Lactente , Londres , Gravidez , Estudos Prospectivos , Inquéritos e QuestionáriosRESUMO
Human chorionic gonadotropin (hCG) is a glycoprotein hormone that is essential for the maintenance of pregnancy. Glycosylation of hCG is known to be essential for its biological activity. "Hyperglycosylated" variants secreted during early pregnancy have been proposed to be involved in initial implantation of the embryo and as a potential diagnostic marker for gestational diseases. However, what constitutes "hyperglycosylation" is not yet fully understood. In this study, we perform comparative N-glycomic analysis of hCG expressed in the same individuals during early and late pregnancy to help provide new insights into hCG function, reveal new targets for diagnostics and clarify the identity of hyperglycosylated hCG. hCG was isolated in urine collected from women at 7 weeks and 20 weeks' gestation. hCG was also isolated in urine from women diagnosed with gestational trophoblastic disease (GTD). We used glycomics methodologies including matrix assisted laser desorption/ionisation-time of flight (MALDI-TOF) mass spectrometry (MS) and MS/MS methods to characterise the N-glycans associated with hCG purified from the individual samples. The structures identified on the early pregnancy (EP-hCG) and late pregnancy (LP-hCG) samples corresponded to mono-, bi-, tri-, and tetra-antennary N-glycans. A novel finding was the presence of substantial amounts of bisected type N-glycans in pregnancy hCG samples, which were present at much lower levels in GTD samples. A second novel observation was the presence of abundant LewisX antigens on the bisected N-glycans. GTD-hCG had fewer glycoforms which constituted a subset of those found in normal pregnancy. When compared to EP-hCG, GTD-hCG samples had decreased signals for tri- and tetra-antennary N-glycans. In terms of terminal epitopes, GTD-hCG had increased signals for sialylated structures, while LewisX antigens were of very minor abundance. hCG carries the same N-glycans throughout pregnancy but in different proportions. The N-glycan repertoire is more diverse than previously reported. Bisected and LewisX structures are potential targets for diagnostics. hCG isolated from pregnancy urine inhibits NK cell cytotoxicity in vitro at nanomolar levels and bisected type glycans have previously been implicated in the suppression of NK cell cytotoxicity, suggesting that hCG-related bisected type N-glycans may directly suppress NK cell cytotoxicity.
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Gonadotropina Coriônica Humana Subunidade beta/metabolismo , Polissacarídeos/metabolismo , Processamento de Proteína Pós-Traducional , Sequência de Carboidratos , Gonadotropina Coriônica Humana Subunidade beta/sangue , Gonadotropina Coriônica Humana Subunidade beta/urina , Feminino , Idade Gestacional , Doença Trofoblástica Gestacional/sangue , Doença Trofoblástica Gestacional/metabolismo , Doença Trofoblástica Gestacional/urina , Glicômica/métodos , Glicosilação , Humanos , Gravidez , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Espectrometria de Massas em TandemRESUMO
AIM: We have assessed the potential predictive ability of the biomarkers activin B and fibronectin (FN1) alone and when added to established markers for triaging patients as being at low or high risk of ectopic pregnancy (EP). We also assessed their use as predictors of viability at 12 weeks gestation. METHODS: Exploratory secondary analysis of a prospective study including all women classified as a pregnancy of known location (PUL) based on transvaginal ultrasonography between January and December 2007 at the early pregnancy unit of St Georges' Hospital (London). We used multinomial logistic regression to assess the diagnostic potential of the biomarkers to triage PUL at high risk of complications (EP or persistent PUL), and standard binary logistic regression to predict first trimester viability at 12 weeks. RESULTS: For discriminating high-risk (n = 16) from low-risk PUL (n = 93), the area under the receiver operating characteristic curve (AUC) was 0.75 (95% confidence interval 0.60-0.85) for activin B and 0.55 (0.41-0.68) for FN1. Adding activin B to a multinomial logistic regression model incorporating ß-hCG ratio and initial progesterone yielded odds ratios of 0.16 (0.05-0.55) for failing vs high-risk PUL and 0.29 (0.07-1.19) for intrauterine vs high-risk PUL and increased the model's AUC from 0.84 to 0.89. At a risk threshold of 5% for high-risk PUL, sensitivity increased from 84% to 87% and specificity from 48% to 64%. For discriminating viable (n = 28) from non-viable (n = 81) pregnancies at 12 weeks, both markers had an AUC of 0.54. CONCLUSIONS: Our results suggested that activin B may be a promising marker to improve PUL triage in addition to established markers.
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The management of women with a pregnancy of unknown location (PUL) can vary significantly and often lacks a clear evidence base. Intensive follow-up is usually required for women with a final outcome of an ectopic pregnancy. This, however, only accounts for a small proportion of women with a pregnancy of unknown PUL location. There remains a clear clinical need to rationalize the follow-up of PUL so women at high risk of having a final outcome of an ectopic pregnancy are followed up more intensively and those PUL at low risk of having an ectopic pregnancy have their follow-up streamlined. This review covers the main management strategies published in the current literature and aims to give clinicians an overview of the most up-to-date evidence that they can take away into their everyday clinical practice when caring for women with a PUL.
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Gravidez Ectópica/diagnóstico , Gravidez Ectópica/terapia , Saúde da Mulher , Biomarcadores/sangue , Gonadotropina Coriônica/sangue , Feminino , Humanos , Gravidez , Ultrassonografia Pré-Natal , Conduta ExpectanteRESUMO
BACKGROUND: Risk models often perform poorly at external validation in terms of discrimination or calibration. Updating methods are needed to improve performance of multinomial logistic regression models for risk prediction. METHODS: We consider simple and more refined updating approaches to extend previously proposed methods for dichotomous outcomes. These include model recalibration (adjustment of intercept and/or slope), revision (re-estimation of individual model coefficients), and extension (revision with additional markers). We suggest a closed testing procedure to assist in deciding on the updating complexity. These methods are demonstrated on a case study of women with pregnancies of unknown location (PUL). A previously developed risk model predicts the probability that a PUL is a failed, intra-uterine, or ectopic pregnancy. We validated and updated this model on more recent patients from the development setting (temporal updating; n = 1422) and on patients from a different hospital (geographical updating; n = 873). Internal validation of updated models was performed through bootstrap resampling. RESULTS: Contrary to dichotomous models, we noted that recalibration can also affect discrimination for multinomial risk models. If the number of outcome categories is higher than the number of variables, logistic recalibration is obsolete because straightforward model refitting does not require the estimation of more parameters. Although recalibration strongly improved performance in the case study, the closed testing procedure selected model revision. Further, revision of functional form of continuous predictors had a positive effect on discrimination, whereas penalized estimation of changes in model coefficients was beneficial for calibration. CONCLUSIONS: Methods for updating of multinomial risk models are now available to improve predictions in new settings. A closed testing procedure is helpful to decide whether revision is preferred over recalibration. Because multicategory outcomes increase the number of parameters to be estimated, we recommend full model revision only when the sample size for each outcome category is large.
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INTRODUCTION: The objective was to validate a virtual reality simulation ultrasound model as a tool for training in the use of transvaginal ultrasonography in gynaecology and early pregnancy. METHODS: Three separate groups consisting of novice and intermediate level residents as well as expert ultrasound examiners were recruited to the study. All were asked to answer a questionnaire regarding demographic data and ultrasound experience. They subsequently completed two modules: basic gynaecology and early pregnancy, followed by corresponding assessments using a high-fidelity simulator (Scantrainer; Medaphor™, Cardiff, UK). Finally, the expert group completed an additional questionnaire about various elements of the simulator using a 5-point Likert scale. RESULTS: Each group consisted of eight participants. Overall, the participants agreed that simulation played a role in training (Novices: 75% (n = 6); Intermediates: 100% (n = 8); Experts: 75% (n = 6)). For the degree of realism of the target objects in the gynaecology and early pregnancy module environments compared to a real-patient environment, the simulator was rated satisfactory or very satisfactory by 88% (n = 7) and 75% (n = 6) of experts, respectively. All experts rated the overall usefulness of the content of the simulator for learning fundamental ultrasound technical skills compared to current training methods to be at least satisfactory. When reviewing the assessment scores, experts scored higher than non-experts in gynaecology (P = 0.002) and early pregnancy modules (P = 0.03). DISCUSSION: Face, content and construct validity were demonstrated by the virtual reality ultrasound simulator, suggesting it may be an effective method for training ultrasound skills in gynaecology and early pregnancy to non-expert residents.
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Since the introduction of the European Working Time Directive, specialist registrars arguably contribute less to clinical service. The purpose of this study was to broadly quantify the service contribution of specialist registrars across a range of specialties and their value to an NHS organisation. A questionnaire-based survey of the clinical activities of specialist registrars in a large NHS trust was undertaken. Simple costing analyses of this -clinical activity were performed. Responses from 66 specialist registrars in 24 specialties showed an average of 51% overall clinical autonomy. Trainees attended an average of 2.7 outpatient clinics per week and spent 3.5 sessions a week doing ward work. Medical trainees took more referrals and attended more clinics. An analysis of costings suggested that surgical trainees might have generated around £700,000 income per year for the trust. Overall, specialist registrars make a substantial contribution to NHS clinical service and are cost-effective.