BACKGROUND AND PURPOSE:

• Oral glucose tolerance tests can be challenging during the COVID-19 pandemic due to social distancing restrictions
  • National guidelines for many countries recommend alternative options for hyperglycemia screening
• Meek et al. (Diabetic Medicine, 2020) evaluated the diagnostic and prognostic performance of oral glucose tolerance tests alternatives

METHODS:

• Retrospective study
• Data sources
  • Cambridge University Hospital NHS Foundation Trust (CUHFT) data
  • OPHELIA prospective observational study, UK
• Participants
  • From CUHFT: Singleton pregnancies with GDM
  • From OPHELIA: Women with ≥1 GDM risk factor
• Study design
  • Receiver-operating characteristic (ROC) curves and unadjusted logistic regression were used to compare
    • Random plasma glucose
    • Fasting plasma glucose
    • HbA1c performance
• Primary outcomes
  • Gestational diabetes (NICE or International Association of Diabetes and Pregnancy Study [IADPS] Groups criteria)
  • Diabetes in pregnancy (WHO criteria)
  • Cesarean delivery
  • LGA
  • Neonatal hypoglycemia
  • NICU admission

RESULTS:

• In CUHFT: 17,736 singleton pregnancies | 826 GDM pregnancies
• In OPHELIA: 361 women with ≥1 GDM risk factor
• GDM diagnosis was significantly associated with
  • Random plasma glucose at 12 weeks
    • AUROC (NICE and IADPS) 0.81 (95% CI, 0.79 to 0.83)
  • Fasting plasma glucose
    • AUROC (NICE): 0.75 (95% CI, 0.65 to 0.85)
    • AUROC (IADPS): 0.92 (95% CI, 0.85 to 0.98)
  • HbA1c at 28 weeks’ gestation
    • AUROC (NICE): 0.83 (95% CI, 0.75 to 0.90)
    • AUROC (IADPS): 0.84 (95% CI, 0.77 to 0.91)
• For a 5% GDM detection rate (similar to detection rate using standard oral glucose testing) the following cut-offs would be required
  • At 12 weeks: Random plasma glucose ≥8.5 mmol/l (153 mg/dL | Sensitivity 42%; Specificity 96%
  • At 28 weeks
    • HbA1c ≥39 mmol/mol (5.7%) | Sensitivity 26%; Specificity 96%
    • Fasting plasma glucose ≥5.2–5.4 mmol/l (93.6 mg/dL to 97.2 mg/dL) | Sensitivity 18–41%; Specificity 97–98%
• These measures predicted some of the pregnancy outcomes

CONCLUSION:

• The following alternative testing strategies can identify pregnant women with hyperglycemia at risk of adverse pregnancy outcomes vs oral glucose testing
  • Random plasma glucose at 12 weeks
  • Fasting plasma glucose
  • HbA1c at 28 weeks
• The authors state that while all 3 approaches can predict obstetric and neonatal outcomes, practice should not be changed post-pandemic without further research and long term data

Learn More – Primary Sources:

Approaches to screening for hyperglycaemia in pregnant women during and after the COVID‐19 pandemic

SOCIETY FOR BIOMEDICAL DIABETES RESEARCH: Conversion of HbA1c values from % to mmol/mol

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