Since the publication in the New England Journal of Medicine (NEJM) in 2000 of the Langer's trial comparing glyburide vs insulin in the treatment of gestational diabetes mellitus (GDM), additional studies of oral agents for the treatment of GDM have been published (observational, randomized controlled trials (RCT), and trials using other drugs like metformin). Some meta-analysis to summarize the evidence have been published: Nicholson 2009 (including 4 RCT addressing different drugs), Dhulkotia 2010 (including 6 RCT addressing different drugs, the meta-analysis combining all drugs altogether), Gui 2013 (including 5 RCT addressing metformin vs insulin). Oral agents are increasingly used for the treatment of GDM. Investigators aim to update the evidence on RCTs comparing glyburide and metformin vs insulin or between them and summarize this evidence using meta-analysis tools. Specifically, investigators aim at producing distinct meta-analyses for each one of the three drug comparisons. This information is not available in the literature since the most recent systematic reviews specifically dealing on oral agents for the treatment of GDM have addressed a single drug comparison (Gui 2013) or have combined different drug comparisons into a single meta-analysis (Dhulkotia 2010)
This project involves the systematic review of RCT addressing the use of glyburide or metformin for the treatment of GDM. The review will include RCT comparing these drugs versus insulin or making direct comparisons between the two oral agents in pregnant women with GDM. Investigators have pre-specified a series of maternal and fetal outcomes of interest. A comprehensive electronic search strategy will be complemented with a search of bibliographies from relevant studies and the contact of authors from the eligible studies regarding issues on study design or information on primary outcomes. The risk of bias of included studies will be analyzed and this information used to perform sensitivity analyses. If possible, data from original studies will be pooled into relative risks for dichotomous outcomes and mean differences for continuous outcomes. Heterogeneity will be explored for all the analyses. Analyses will be undertaken using a fixed effects model that will be repeated using a random effects model in case of substantial heterogeneity. Results of the systematic review will be published following PRISMA guidance.
Study Type
OBSERVATIONAL
Enrollment
2,509
Affecting groups 1 and 2
Affecting groups 3 and 4
Affecting groups 5 and 6
Hospital de la Santa Creu i Sant Pau
Barcelona, Barcelona, Spain
3rd trimester glycated hemoglobin
mean difference of 3rd trimester glycated hemoglobin
Time frame: 3rd trimester of pregnancy
total maternal weight gain
mean difference of total maternal weight gain (as defined by the authors)
Time frame: during pregnancy
severe maternal hypoglycemia
relative risk of severe maternal hypoglycemia (as defined by the authors)
Time frame: from enrollment to delivery
preeclampsia
relative risk of preeclampsia (as defined by the authors)
Time frame: during pregnancy or puerperium
cesarean section
relative risk of cesarean section (as defined by the authors)
Time frame: at the end of pregnancy
gestational age at birth
mean difference of gestational age at birth (as defined by the authors)
Time frame: at birth
preterm birth
relative risk of preterm birth (as defined by the authors)
Time frame: at birth
birthweight
mean difference of birthweight (as defined by the authors)
Time frame: at birth
macrosomia
relative risk of macrosomia (defined as birthweight \>=4000 g)
Time frame: at birth
large-for-gestational age newborn
relative risk of large-for-gestational age newborn (as defined by the authors)
Time frame: at birth
small-for-gestational age newborn
relative risk of small-for-gestational age newborn (as defined by the authors)
Time frame: at birth
neonatal hypoglycemia
relative risk of neonatal hypoglycemia (as provided by the authors)
Time frame: in the neonatal period
perinatal mortality
relative risk of perinatal mortality (as defined by the authors)
Time frame: in the perinatal period
insulin treatment
relative risk of insulin treatment (for trials comparing metformin vs glyburide)
Time frame: from enrollment to delivery
fasting blood glucose
mean difference of fasting blood glucose (as defined by the authors)
Time frame: in the period from enrollment to delivery
postprandial blood glucose
mean difference of postprandial blood glucose (as defined by the authors)
Time frame: in the period from enrollment to delivery
maternal weight gain since enrollment
mean difference of maternal weight gain since enrollment (as defined by the authors)
Time frame: in the period from enrollment to delivery
pregnancy-induced hypertension
relative risk of pregnancy-induced hypertension (as defined by the authors)
Time frame: during pregnancy
induction of labour
relative risk of induction of labour (as described by the authors)
Time frame: at the end of pregnancy
cord C peptide
mean difference of cord C peptide (as defined by the authors)
Time frame: at birth
cord insulin
mean difference of cord insulin (as defined by the authors)
Time frame: at birth
abnormal 1 min Apgar
relative risk of abnormal 1 min Apgar (defined as lower than 7)
Time frame: at birth
abnormal 5 min Apgar
relative risk of abnormal 5 min Apgar (defined as lower than 7)
Time frame: at birth
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obstetric trauma
relative risk of obstetric trauma (as defined by the authors)
Time frame: at birth
severe neonatal hypoglycemia
relative risk of severe neonatal hypoglycemia (as defined by the authors)
Time frame: in the neonatal period
neonatal jaundice
relative risk of neonatal jaundice (as defined by the authors)
Time frame: in the neonatal period
significant respiratory distress
relative risk of significant respiratory distress (described as respiratory distress syndrome or requiring respiratory support)
Time frame: in the neonatal period
stillbirth
relative risk of stillbirth (as defined by the authors)
Time frame: in the antenatal period
neonatal mortality
relative risk of neonatal mortality (as defined by the authors)
Time frame: in the neonatal period
Neonatal Intensive Care Unit (NICU) admittance
relative risk of NICU admittance (as defined by the authors)
Time frame: in the neonatal period