Inter- and intra-observer variability in fetal ductus venosus blood flow measurements in high-risk fetuses at 26-32 weeks

OBJECTIVES

Early preterm fetal growth restriction is a significant contributor to perinatal morbidity and mortality. The ductus venosus pulsatility index for veins (DV PIV) is proposed as a monitoring tool because it appears to improve perinatal outcomes. The test characteristics and robustness of DV PIV have been inadequately described. The aim of this study was to investigate inter- and intra-observer variability of DV PIV.

STUDY DESIGN

Nineteen women with a gestational age between 26 and 32 completed weeks were included in this study. Doppler sonographic fetal assessment was performed by two independent maternal-fetal medicine specialists. Each sonographer alternately performed three flow tracings for each participant, in the absence of the other sonographer (six tracings in total per patient). DV PIV was calculated automatically from stored tracings by a third researcher. Inter- and intra-observer variability of DV PIV and limits of agreement were assessed using the Bland-Altman method. Comparison of the distribution was performed with Kendall's related samples test, and the intraclass correlation coefficient (ICC) was calculated.

RESULTS

In total, 114 DV measurements were taken from 19 participants with a median age of 31 years [interquartile range (IQR) 26-34 years] at a median gestational age of 28 weeks (IQR 27-29 weeks). The proportional limits of agreement for intra-observer variation were -0.48 to 0.48 and -0.39 to 0.62 for the two observers. ICCs were 0.66 [95% confidence interval (CI) 0.42-0.84] and 0.68 (95% CI 0.45-0.85). The proportional limits of agreement for inter-observer variation were -0.29 to 0.19 with an ICC of 0.89 (95% CI 0.73-0.96).

CONCLUSION

Inter-observer variation was far less than intra-observer variation, probably due to mitigation of biological variation by averaging three measurements. DV PIV has acceptable test characteristics for use in a clinical setting when the average of at least three consecutive measurements is used.

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.

TRIAL REGISTRATION NUMBER

NTR6134; Pre-results.