Role of continuous glucose monitoring in the management of diabetic pregnancy

Oral glucose tolerance test and continuous glucose monitoring for gestational diabetes diagnosis: a survey study of women and health care professionals

AIMS

The oral glucose tolerance test (OGTT), used for gestational diabetes mellitus (GDM) diagnosis for over 65 years, has poor acceptability and tolerability. Continuous glucose monitoring is being considered as potential alternative. The aim of our study was to formally assess women's and health care professionals' perception of both tests as diagnostic tools for GDM.

METHODS

Participants in a pilot study on continuous glucose monitoring for GDM diagnosis were invited to fill two questionnaires, each of 6 Likert-scale and one optional open-ended question. A range of healthcare practitioners were also invited to fill a questionnaire of 13 Likert-scale and 7 optional open-ended questions.

RESULTS

Sixty women completed the OGTT and 70 the continuous glucose monitoring questionnaire. OGTT was reported as poorly acceptable. Continuous glucose monitoring was described as significantly more tolerable (81% vs 27% 5/5 general acceptability rate, p < 0.001); ninety-three percent of the participants would recommend it for GDM diagnosis. Thirty health care professionals completed the survey. Most of them (73%) had confidence in OGTT as a diagnostic test for GDM with 66% raising some concerns. Doubts on continuous glucose monitoring were raised in terms of costs, accessibility and accuracy for GDM diagnosis due to "lack of evidence".

CONCLUSIONS

Continuous glucose monitoring was substantially better tolerated for women than OGTT. Current lack of evidence for diagnostic accuracy for GDM underlines the need for studies on correlation between continuous glucose monitoring parameters and pregnancy outcomes to strengthen evidence for its use as diagnostic test for GDM.

Development and evaluation of an online questionnaire to identify women at high and low risk of developing gestational diabetes mellitus

BACKGROUND

Established risk factors for Gestational Diabetes Mellitus (GDM) include age, ethnicity, family history of diabetes and previous GDM. Additional significant influences have recently been demonstrated in the literature. The oral glucose tolerance test (OGTT) used for GDM diagnosis has sub-optimal sensitivity and specificity, thus often results in GDM misdiagnoses. Comprehensive screening of risk factors may allow more targeted monitoring and more accurate diagnoses, preventing the devastating consequences of untreated or misdiagnosed GDM. We aimed to develop a comprehensive online questionnaire of GDM risk factors and triangulate it with the OGTT and continuous glucose monitoring (CGM) parameters to better evaluate GDM risk and diagnosis.

METHODS

Pregnant women participating in two studies on the use of CGM for GDM were invited to complete the online questionnaire. A risk score, based on published literature, was calculated for each participant response and compared with the OGTT result. A total risk score (TRS) was then calculated as a normalised sum of all risk factors. Triangulation of OGTT, TRS and CGM score of variability (CGMSV) was analysed to expand evaluation of OGTT results.

RESULTS

Fifty one women completed the questionnaire; 29 were identified as 'high-risk' for GDM. High-risk ethnic background (p < 0.01), advanced age, a family diabetic history (p < 0.05) were associated with a positive OGTT result. The triangulation analysis (n = 45) revealed six (13%) probable misdiagnoses (both TRS and CGMSV discordant with OGTT), consisting of one probable false positive and five probable false negative by OGTT results.

CONCLUSIONS

This study identified pregnant women at high risk of developing GDM based on an extended evaluation of risk factors. Triangulation of TRS, OGTT and CGMSV suggested potential misdiagnoses of the OGTT. Future studies to explore the correlation between TRS, CGMSV and pregnancy outcomes as well as additional GDM pregnancy biomarkers and outcomes to efficiently evaluate OGTT results are needed.

Effects of continuous glucose monitoring on maternal and neonatal outcomes in perinatal women with diabetes: A systematic review and meta-analysis of randomized controlled trials

AIMS

This systematic review aims to assess the effects of continuous glucose monitoring (CGM) on maternal and neonatal outcomes in perinatal women with diabetes.

METHODS

A three-step comprehensive search was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guideline. Randomized controlled trials (RCTs) were retrieved from international databases of PubMed, Embase, Cochrane Library, CINAHL, PsycINFO and Scopus from their respective inception dates until 5th January 2021. Comprehensive Meta-Analysis Software Version 3 was used. The overall effect was determined using Hedges' g. Cochrane collaboration's tool version 1 and grading of recommendations, assessment, development and evaluation criteria were used for quality assessment.

RESULTS

A total of 1215 records were identified and 10 RCTs involving a total of 1358 perinatal women were selected. The meta-analysis revealed that CGM significantly improved HbA1c levels (g = -0.43, 95% CI: -0.63, -0.22), lowered cesarean section rate (g = -0.17, 95% CI: -0.33, -0.02) and neonatal birth weight (g = -0.16, 95% CI: -0.27, -0.04) when compared to the comparator. The majority (86.67%) has a low risk of biases and certainty of evidence ranged from very low to moderate.

CONCLUSION

CGM improves maternal and neonatal outcomes. Future studies should use well-designed large-scale trials.

Effect of a CGMS and SMBG on Maternal and Neonatal Outcomes in Gestational Diabetes Mellitus: a Randomized Controlled Trial

In this study, we sought to investigate the effects of a continuous glucose monitoring system (CGMS) on maternal and neonatal outcomes. A total of 106 women with gestational diabetes mellitus (GDM) in gestational weeks 24–28 were randomly allocated to the antenatal care plus CGMS group or the self-monitoring blood glucose (SMBG) group. The CGMS group was subdivided into early and late subgroups. There were no significant differences in prenatal or obstetric outcomes, e.g., caesarean delivery rate, Apgar score at 5 min, macrosomia or neonatal hypoglycaemia, between the CGMS and SMBG groups. The CGMS group had lower glycated haemoglobin (HbA1C) levels than the SMBG group; however, the difference was not statistically significant. The proportion of GDM women with excessive gestational weight gain was lower in the CGMS group than in the SMBG group (33.3% vs. 56.4%, P = 0.039), and women who initiated CGMS earlier gained less weight (P = 0.017). The mode of blood glucose monitoring (adjusted OR 2.40; 95% CI 1.030–5.588; P = 0.042) and pre-pregnancy BMI (adjusted OR 0.578; 95% CI 0.419–0.798; P = 0.001) were independent factors for weight gain. In conclusion, early CGMS for GDM mothers reduces gestational weight gain. A follow-up study with a large cohort is needed.

The efficacy and effectiveness of continuous glucose monitoring during pregnancy: a systematic review

OBJECTIVE

Diabetic pregnancies carry a high risk for both mother and child, especially when glycemic control is poor. A novel technique that aims to improve glycemic control is the continuous glucose monitor (CGM). This tool is already in use to improve pregnancy outcome. This review presents the available evidence on the efficacy of CGM use in pregnancy and the effectiveness on pregnancy outcome.

METHODS

A systematic search was conducted using PubMed, EMBASE, and the Cochrane Libraries for articles on CGM in pregnancy. We evaluated the selected articles with particular attention for clinical and cost-effectiveness of CGM to improve pregnancy outcome.

RESULTS

We retrieved 5032 articles, 11 of which remained as relevant after selection according to predefined criteria. Most studies were limited to the evaluation of the role of CGM on clinical decision making. Only 2 studies were randomized controlled trials (RCTs) evaluating the effect on pregnancy outcome. One small RCT on retrospective CGM showed a significant reduction in third-trimester HbA1c and a significant reduction in neonatal macrosomia. A second RCT on real-time CGM did not show any effect on either glycemic control or on pregnancy outcome.

CONCLUSIONS

Current evidence on the efficacy of CGM on improving glycemic control during pregnancy as well as on the effectiveness on pregnancy outcome is limited to 2 RCTs with contradicting results. Evidence on the cost-effectiveness is lacking. Further proper RCTs on the effectiveness and cost-effectiveness of CGM in pregnancy are required before wide implementation in practice.

Continuous glucose monitors: current status and future developments

PURPOSE OF REVIEW

Advances in diabetes technologies allow patients to manage their diabetes with greater precision and flexibility. Many recent studies show that continuous glucose monitors (CGMs) can be used to tighten glycemic control safely and to ease certain burdens of diabetes self-management.

RECENT FINDINGS

The following summary reflects the most recent findings in CGM and provides an overall review of who would most benefit from CGM use. Benefits of CGM may vary based on age, type of diabetes, pregnancy, health, sleep, or heart rate. Accuracy and reliability are critical in current uses of CGM and especially for new and future systems that automate insulin partially (e.g., low glucose suspend) or entirely (e.g., 'fully closed-loop' artificial pancreas). Clinicians are simultaneously testing available products in new patient groups such as the critically ill and type 2 diabetes patients not using mealtime insulin.

SUMMARY

In a widening set of circumstances, use of CGM has been shown to promote safer and more effective glycemic control than self-monitoring of blood glucose. Imperfections remain in certain scenarios such as hypoglycemia and in certain populations such as young children. Ongoing research on sensors and calibration software should translate to better systems.