October Cochrane review round-up
medwireNews: The two diabetes-related Cochrane reviews published in October focused on diabetes during pregnancy; the first covered different methods of glucose monitoring, while the second compared oral antidiabetic agents with insulin, with both concluding that better quality research is needed to draw firm conclusions.
In the first review, conducted by Emily Shepherd (The University of Adelaide, South Australia) and team, evidence from 11 randomized controlled trials (RCTs) that included 1272 women with gestational diabetes showed no significant difference between different methods of glucose monitoring in the rates of pre-eclampsia or pregnancy-induced hypertension, cesarean section, neonatal death, babies born large-for-gestational age, and neonatal hypoglycemia.
The comparisons included telemedicine versus standard care, self-monitoring versus periodic glucose monitoring, and continuous glucose monitoring (CGM) versus less frequent self-monitoring.
One RCT, with 66 participants, found that babies born to women randomly assigned to receive postprandial glucose monitoring were less likely to be born large-for-gestational age than those born to women randomly assigned to preprandial glucose monitoring.
However, the authors caution that the findings were limited by small sample sizes and variable methodological quality. Indeed, they considered all of the trials to be at moderate to high risk for bias.
Shepherd et al conclude that it remains unclear which method is best for monitoring patients with gestational diabetes.
They add that further large, well-designed, RCTs, perhaps reporting on the standard maternal and infant outcomes used in their review, are needed “to assess the effects of different methods and settings for blood glucose monitoring for women with [gestational diabetes] in order to improve outcomes for women and their babies in the short and long term.”
Of note, the findings of the CONCEPTT trial in women with type 1 diabetes, published in The Lancetearlier this year, indicate that the use of CGM during pregnancy improves glycemic control and neonatal outcomes relative to standard glucose monitoring.
In the second review, Joanna Tieu, also from the University of Adelaide, and team updated a review from 2010 that compared oral antidiabetic agents with insulin in women with diabetes, impaired glucose tolerance, or previous gestational diabetes who are planning a pregnancy, or pregnant women with pre-existing diabetes.
They identified three RCTs, including 241 women with type 2 diabetes diagnosed before or during pregnancy, and found no difference between metformin – the only oral agent used – and insulin in the risk for pre-eclampsia, induction of labour, and having a baby that is large-for-gestational age.
But the data, which the researchers considered to be of low quality, suggested that women receiving metformin were less likely to have pregnancy-induced hypertension or a cesarean section compared with those receiving insulin while their babies were less likely to have hypoglycemia.
Tieu and team point out that the three RCTs they reviewed “did not report on many important short- and long-term outcomes, including perineal trauma and a combined outcome of infant death or morbidity, postnatal depression and weight retention for mothers, and adiposity or disability in childhood or adulthood for infants.”
They conclude that “further high-quality RCTs that compare any combination of oral anti-diabetic agent, insulin and dietary and lifestyle advice for these women are needed.”
By Laura Cowen
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