medwireNews: Pregnant women with type 1 diabetes can achieve similar glucose control regardless of whether they use insulin degludec or detemir, show the results of the randomised EXPECT trial.
As reported in The Lancet Diabetes & Endocrinology, Elisabeth Mathiesen (University of Copenhagen, Denmark) and team recruited 225 women with type 1 diabetes who were either pregnant or planning a pregnancy, 188 of whom were pregnant during the course of the trial.
These women had relatively low glycated haemoglobin (HbA1c) levels at the start of their pregnancy, at an average of 6.5–6.6% (48–49 mmol/mol). The last HbA1c measurement before delivery averaged 6.2% (45 mmol/mol) among women randomly assigned to take insulin degludec and 6.3% (46 mmol/mol) among those given insulin detemir, making degludec statistically noninferior to detemir.
At the last planned measurement before delivery, 43% of women in the degludec group had an HbA1c of 6.0% or less, as did 37% of those in the detemir group. The corresponding rates for a value of 6.5% or below were 69% and 63%.
Fasting plasma glucose levels averaged 7.2 mmol/L in both groups at baseline and were 6.2 and 6.8 mmol/L in the degludec and detemir groups, respectively, at the last planned measurement before delivery.
The two insulins also gave similar maternal safety outcomes, with nocturnal hypoglycaemia occurring in 78% and 73% of women taking degludec and detemir, respectively, and severe hypoglycaemia in 5% and 2%. Likewise, there were no treatment-related differences in foetal and neonatal outcomes.
In a linked commentary, Helen Murphy (Cambridge University Hospitals NHS Foundation Trust, UK) says that “[t]he EXPECT results provide reassurance that detemir and degludec can be used safely before and during pregnancy.”
However, she questions use of a 0.4% noninferiority margin for HbA1c given that “very small changes in maternal glucose” of approximately 0.2% were “associated with large neonatal health benefits” in the CONCEPTT trial.
“Therefore, larger HbA1c differences […] might miss clinically relevant differences in neonatal health outcomes”, she says.
Murphy also highlights the “striking” gap between the fasting plasma glucose levels achieved in the trial and the recommended target of 4.0–5.0 mmol/L, saying: “It is surprising that even highly motivated trial participants, with near-optimal first trimester HbA1c struggled to maintain target glucose concentrations throughout pregnancy.”
The EXPECT findings therefore “also serve as a reminder of the gap that remains between guideline recommended glucose targets and the reality for pregnant women with type 1 diabetes striving to achieve them”, she concludes.
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Lancet Diabetes Endocrinol 2023; doi:10.1016/S2213-8587(22)00307-2
Lancet Diabetes Endocrinol 2023; doi:10.1016/S2213-8587(22)00341-2