Prognostic models versus single risk factor approach in first-trimester selective screening for gestational diabetes mellitus: a prospective population-based multicentre cohort study

Objectives: To evaluate whether (1) first-trimester prognostic models for gestational diabetes mellitus (GDM) outperform the currently used single risk factor approach, and (2) a first-trimester random venous glucose measurement improves model performance. Design: Prospective population-based multicentre cohort. Setting: Thirty-one independent midwifery practices and six hospitals in the Netherlands. Population: Women recruited before 14 weeks of gestation without pre-existing diabetes. Methods: The single risk factor approach (presence of at least one risk factor: BMI ≥30 kg/m2, previous macrosomia, history of GDM, positive first-degree family history of diabetes, non-western ethnicity) was compared with the four best performing models in our previously published external validation study (Gabbay-Benziv 2014, Nanda 2011, Teede 2011, van Leeuwen 2010) with and without the addition of glucose. Main outcome measures: Discrimination was assessed by c-statistics, calibration by calibration plots, added value of glucose by the likelihood ratio chi-square test, net benefit by decision curve analysis and reclassification by reclassification plots. Results: Of the 3723 women included, a total of 181 (4.9%) developed GDM. The c-statistics of the prognostic models were higher, ranging from 0.74 to 0.78 without glucose and from 0.78 to 0.80 with glucose, compared with

The Impact of a Standardized Pre-visit Laboratory Testing Panel in the Internal Medicine Outpatient Clinic: a Controlled “On-Off” Trial

Background: In several settings, a shorter time to diagnosis has been shown to lead to improved clinical outcomes. The implementation of a rapid laboratory testing allows for a pre-visit testing in the outpatient clinic, meaning that test results are available during the first outpatient visit. Objective: To determine whether the pre-visit laboratory testing leads to a shorter time to diagnosis in the general internal medicine outpatient clinic. Design: An “on-off” trial, allocating subjects to one of two treatment arms in consecutive alternating blocks. Participants: All new referrals to the internal medicine outpatient clinic of a university hospital were included, excluding second opinions. A total of 595 patients were eligible; one person declined to participate, leaving data from 594 patients for analysis. Intervention: In the intervention group, patients had a standardized pre-visit laboratory testing before the first visit. Main Measures: The primary outcome was the time to diagnosis. Secondary outcomes were the correctness of the preliminary diagnosis on the first day, health care utilization, and patient and physician satisfaction. Key Results: There was no difference in time to diagnosis between the two groups (median 35 days vs 35 days; hazard ratio 1.03 [0.87–1.22]; p =.71). The pre-visit testing group had higher proportions of both correct preliminary diagnoses on day 1 (24% vs 14%; p =.003) and diagnostic workups being completed on day 1 (10% vs 3%; p <.001). The intervention group had more laboratory tests done (50.0 [interquartile range (IQR) 39.0–69.0] vs 43.0 [IQR 31.0–68.5]; p <.001). Otherwise, there were no differences between the groups. Conclusions: Pre-visit testing did not lead to a shorter overall time to diagnosis. However, a greater proportion of patients had a correct diagnosis on the first day. Further studies should focus on customizing pre-visit laboratory panels, to improve their efficacy. Trial Registration: NL500

SUGAR-DIP trial: Oral medication strategy versus insulin for diabetes in pregnancy, study protocol for a multicentre, open-label, non-inferiority, randomised controlled trial

Introduction In women with gestational diabetes mellitus (GDM) requiring pharmacotherapy, insulin was the established first-line treatment. More recently, oral glucose lowering drugs (OGLDs) have gained popularity as a patient-friendly, less expensive and safe alternative. Monotherapy with metformin or glibenclamide (glyburide) is incorporated in several international guidelines. In women who do not reach sufficient glucose control with OGLD monotherapy, usually insulin is added, either with or without continuation of OGLDs. No reliable data from clinical trials, however, are available on the effectiveness of a treatment strategy using all three agents, metformin, glibenclamide and insulin, in a stepwise approach, compared with insulin-only therapy for improving pregnancy outcomes. In this trial, we aim to assess the clinical effectiveness, cost-effectiveness and patient experience of a stepwise combined OGLD treatment protocol, compared with conventional insulin-based therapy for GDM. Methods The SUGAR-DIP trial is an open-label, multicentre randomised controlled non-inferiority trial. Participants are women with GDM who do not reach target glycaemic control with modification of diet, between 16 and 34 weeks of gestation. Participants will be randomised to either treatment with OGLDs, starting with metformin and supplemented as needed with glibenclamide, or randomised to treatment with insulin. In women who do not reach target glycaemic control with combined metformin and glibenclamide, glibenclamide will be substituted with insulin, while continuing metformin. The primary outcome will be the incidence of large-for-gestational-age infants (birth weight >90th percentile). Secondary outcome measures are maternal diabetes-related endpoints, obstetric complications, neonatal complications and cost-effectiveness analysis. Outcomes will be analysed according to the intention-to-treat principle. Ethics and dissemination The study protocol was approved by the Ethics Committee of the Utrecht University Medical Centre. Approval by the boards of management for all participating hospitals will be obtained. Trial results will be submitted for publication in peer-reviewed journals

Improving the methodological framework for diagnostic studies

The salient question to ask when evaluating a diagnostic test is “Does the use of this test lead to improved health outcomes?”. Tests lead to improved health outcomes by identifying patients who will benefit from clinical action. Therefore, to improve health outcomes, a test must be able to distinguish between people with and without the disease of interest with a certain degree of accuracy. The current methodological framework for estimating diagnostic accuracy assumes that there is a “gold” reference standard to which the test(s) under study can be compared. This framework is often challenged by the fact that there is no such test or method that classifies disease status without error and that can be performed in all study participants. The first of the two aims of this thesis is to explore and improve methods for dealing with the challenge of a lack of a “gold” standard in diagnostic accuracy research. We address this challenge by describing the corresponding methods to deal with it and, more importantly, by providing recommendations on their optimal use. We cover methods for dealing with imperfect reference standards, namely composite reference standards, panel diagnosis, and latent class analysis as well address the situation of not being able to perform the preferred reference standard in all study participants. The ability to obtain unbiased estimates of test accuracy in a single study is foundational to answering the question whether a test leads to improved health outcomes. The next level of evidence comes from systematic reviews in which the results of multiple primary studies are summarized. Therefore, the second aim of this thesis is to explore and improve the study of diagnostic tests on an aggregate level. We focus on how variability in results between studies is currently being investigated and, based on these findings, provide further guidance. Although a precise and accurate estimate of test performance is often helpful in deciding whether to implement a test, it is not always essential. As we argue in the general discussion, failure to think outside the diagnostic accuracy framework can even lead to adverse clinical outcomes in some situations, particularly when evaluating new highly sensitive tests that challenge the existing reference standards. We conclude this thesis by summarizing alternative methods for evaluating the clinical benefit of such tests

Forcing dichotomous disease classification from reference standards leads to bias in diagnostic accuracy estimates: A simulation study

Objectives: The objective of this study was to study the impact of ignoring uncertainty by forcing dichotomous classification (presence or absence) of the target disease on estimates of diagnostic accuracy of an index test.Study Design and Setting: We evaluated the bias in estimated index test accuracy when forcing an expert panel to make a dichotomous target disease classification for each individual. Data for various scenarios with expert panels were simulated by varying the number and accuracy of "component reference tests" available to the expert panel, index test sensitivity and specificity, and target disease prevalence.Results: Index test accuracy estimates are likely to be biased when there is uncertainty surrounding the presence or absence of the target disease. Direction and amount of bias depend on the number and accuracy of component reference tests, target disease prevalence, and the true values of index test sensitivity and specificity.Conclusion: In this simulation, forcing expert panels to make a dichotomous decision on target disease classification in the presence of uncertainty leads to biased estimates of index test accuracy. Empirical studies are needed to demonstrate whether this bias can be reduced by assigning a probability of target disease presence for each individual, or using advanced statistical methods to account for uncertainty in target disease classification. (C) 2019 Elsevier Inc. All rights reserved.Clinical epidemiolog

Strategies to reduce the use of low-value medical tests in primary care: a systematic review

BACKGROUND: It is recognised that medical tests are overused in primary care; however, it is unclear how best to reduce their use. AIM: To identify which strategies are effective in reducing the use of low-value medical tests in primary care settings. DESIGN AND SETTING: Systematic review. METHOD: The databases MEDLINE, EMBASE, and Rx for Change were searched (January 1990 to November 2019) for randomised controlled trials (RCTs) that evaluated strategies to reduce the use of low-value medical tests in primary care settings. Two reviewers selected eligible RCTs, extracted data, and assessed their risk of bias. RESULTS: Of the 16 RCTs included in the review, 11 reported a statistically significant reduction in the use of low-value medical tests. The median of the differences between the relative reductions in the intervention and control arms was 17% (interquartile range 12% to 24%). Strategies using reminders or audit/feedback showed larger reduction than those without these components (22% versus 14%, and 22% versus 13%, respectively) and patient-targeted strategies showed larger reductions than those not targeted at patients (51% versus 17%). Very few studies investigated the sustainability of the effect, adverse events, cost-effectiveness, or patient-reported outcomes related to reducing the use of low-value tests. CONCLUSION: This review indicates that it is possible to reduce the use of low-value medical tests in primary care, especially by using multiple components including reminders, audit/feedback, and patient-targeted interventions. To implement these strategies widely in primary care settings, more research is needed not only to investigate their effectiveness, but also to examine adverse events, cost-effectiveness, and patient-reported outcomes

Use of expert panels to define the reference standard in diagnostic research : a systematic review of published methods and reporting

BACKGROUND: In diagnostic studies, a single and error-free test that can be used as the reference (gold) standard often does not exist. One solution is the use of panel diagnosis, i.e., a group of experts who assess the results from multiple tests to reach a final diagnosis in each patient. Although panel diagnosis, also known as consensus or expert diagnosis, is frequently used as the reference standard, guidance on preferred methodology is lacking. The aim of this study is to provide an overview of methods used in panel diagnoses and to provide initial guidance on the use and reporting of panel diagnosis as reference standard. METHODS AND FINDINGS: PubMed was systematically searched for diagnostic studies applying a panel diagnosis as reference standard published up to May 31, 2012. We included diagnostic studies in which the final diagnosis was made by two or more persons based on results from multiple tests. General study characteristics and details of panel methodology were extracted. Eighty-one studies were included, of which most reported on psychiatry (37%) and cardiovascular (21%) diseases. Data extraction was hampered by incomplete reporting; one or more pieces of critical information about panel reference standard methodology was missing in 83% of studies. In most studies (75%), the panel consisted of three or fewer members. Panel members were blinded to the results of the index test results in 31% of studies. Reproducibility of the decision process was assessed in 17 (21%) studies. Reported details on panel constitution, information for diagnosis and methods of decision making varied considerably between studies. CONCLUSIONS: Methods of panel diagnosis varied substantially across studies and many aspects of the procedure were either unclear or not reported. On the basis of our review, we identified areas for improvement and developed a checklist and flow chart for initial guidance for researchers conducting and reporting of studies involving panel diagnosis. Please see later in the article for the Editors' Summary

RSV prevention in infancy and asthma in later life - Authors' reply

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Pessary or Progesterone to Prevent Preterm delivery in women with short cervical length: the Quadruple P randomised controlled trial

Contains fulltext : 177872.pdf (publisher's version ) (Open Access)BACKGROUND: Preterm birth is in quantity and in severity the most important topic in obstetric care in the developed world. Progestogens and cervical pessaries have been studied as potential preventive treatments with conflicting results. So far, no study has compared both treatments. METHODS/DESIGN: The Quadruple P study aims to compare the efficacy of vaginal progesterone and cervical pessary in the prevention of adverse perinatal outcome associated with preterm birth in asymptomatic women with a short cervix, in singleton and multiple pregnancies separately. It is a nationwide open-label multicentre randomized clinical trial (RCT) with a superiority design and will be accompanied by an economic analysis. Pregnant women undergoing the routine anomaly scan will be offered cervical length measurement between 18 and 22 weeks in a singleton and at 16-22 weeks in a multiple pregnancy. Women with a short cervix, defined as less than, or equal to 35 mm in a singleton and less than 38 mm in a multiple pregnancy, will be invited to participate in the study. Eligible women will be randomly allocated to receive either progesterone or a cervical pessary. Following randomization, the silicone cervical pessary will be placed during vaginal examination or 200 mg progesterone capsules will be daily self-administered vaginally. Both interventions will be continued until 36 weeks gestation or until delivery, whichever comes first. Primary outcome will be composite adverse perinatal outcome of perinatal mortality and perinatal morbidity including bronchopulmonary dysplasia, intraventricular haemorrhage grade III and IV, periventricular leukomalacia higher than grade I, necrotizing enterocolitis higher than stage I, Retinopathy of prematurity (ROP) or culture proven sepsis. These outcomes will be measured up until 10 weeks after the expected due date. Secondary outcomes will be, among others, time to delivery, preterm birth rate before 28, 32, 34 and 37 weeks, admission to neonatal intensive care unit, maternal morbidity, maternal admission days for threatened preterm labour and costs. DISCUSSION: This trial will provide evidence on whether vaginal progesterone or a cervical pessary is more effective in decreasing adverse perinatal outcome in both singletons and multiples. TRIAL REGISTRATION: Trial registration number: NTR 4414 . Date of registration January 29th 2014

A reduced size of the ovarian follicle pool is associated with an increased risk of a trisomic pregnancy in IVF-treated women

BACKGROUND: The increased risk of a trisomic pregnancy with a woman's age arises from an increased rate of meiotic non-disjunction in the oocytes. It has been hypothesized that the increase in meiotic errors is related to the decreasing number of oocytes with age. Our aim was to assess the relation between trisomic pregnancy and three parameters of oocyte quantity. METHODS: In a Dutch nationwide database on in vitro fertilization (IVF) treatment from 1983 to 1995, we identified 28 women with a trisomic pregnancy conceived via or within 1 year from IVF treatment. We selected five age-matched controls with a healthy child for each trisomy case. We performed a case-control study to examine whether trisomy cases more often had a history of ovarian surgery and a lower response to ovarian hyperstimulation than controls. Subsequently, cases and controls were followed to compare the incidence of signs of menopause at the end of the study period as self-reported by questionnaire. RESULTS: Logistic regression analysis showed an association between trisomic pregnancy and a history of ovarian surgery [odds ratio (OR) 3.3; 95% confidence interval (CI): 1.0-10.5; P = 0.04] and between trisomic pregnancy and retrieval of &lt; or = 4 oocytes during IVF treatment (OR 4.0; 95% CI: 1.4-11.5; P = 0.01). The adjusted OR for signs of menopause associated with trisomic pregnancy was 5.7 (95% CI: 1.1-29.9; P = 0.04). CONCLUSIONS: Our results suggest that IVF-treated women with a reduced ovarian follicle pool are at increased risk of a trisomic pregnancy, independent of their age. Our findings support the hypothesis that follicle pool size and not chronological age determines a woman's trisomy risk. Since a questionnaire was used, we cannot fully exclude the possibility of selection bias in this study.<br/