The effectiveness of pharmacological and lifestyle interventions to reduce the risk of diabetes and hyperglycaemia following gestational diabetes: A systematic review and meta-analysis.

AIMS: To synthesize the available evidence to better understand the effectiveness of interventions to prevent or delay hyperglycaemia and Type 2 diabetes mellitus (T2DM) postnatally in women with current or previous gestational diabetes mellitus (GDM).

METHODS: We searched five databases up to December 2020 for primary peer-reviewed articles reporting postpartum glycaemic outcomes in women with (previous) GDM following pharmacological or lifestyle intervention. Outcomes were relative risk of T2DM or continuous measures of glycaemia, change or at follow-up. A minimum of two studies evaluating the same intervention-outcome combination were needed to conduct meta-analyses, otherwise studies were described narratively. Meta-regression was used to evaluate whether associations varied by additional variables. We assessed risk of bias using the Critical Appraisal Skills Programme checklist. PROSPERO record CRD42018102380.

RESULTS: We included 31 studies in the review with a total sample size of 8624 participants, and 26 studies in meta-analyses. Two-thirds of studies followed up participants at 1 year or less. Pharmacological interventions were associated with reduced risk of T2DM (0.80 [95% CI 0.64-1.00], n = 6 studies), as were lifestyle interventions albeit with a smaller effect size (0.88 [95% CI 0.76-1.01], n = 12 studies). Dietary and physical activity interventions were associated with a small reduction in fasting plasma glucose, particularly in longer interventions, but inconsistent effects were seen for other continuous outcomes.

CONCLUSIONS: Although possibly due to chance, interventions to reduce hyperglycaemia after GDM may be effective. Future research should improve understanding of how interventions affect glucose control and how to optimise interventions for this population.