Effectiveness and acceptability of metformin in preventing the onset of type 2 diabetes after gestational diabetes in postnatal women: a protocol for a randomised, placebo-controlled, double-blind feasibility trial—Optimising health outcomes with Metformin to prevent diAbetes After pregnancy (OMAhA)

Metformin in the prevention of type 2 diabetes after gestational diabetes in postnatal women (OMAhA): a UK multicentre randomised, placebo-controlled, double-blind feasibility trial with nested qualitative study

OBJECTIVE

To determine the feasibility of a definitive trial of metformin to prevent type 2 diabetes in the postnatal period in women with gestational diabetes.

DESIGN

A multicentre, placebo-controlled, double-blind randomised feasibility trial with qualitative evaluation.

SETTING

Three inner-city UK National Health Service hospitals in London.

PARTICIPANTS

Pregnant women with gestational diabetes treated with medication.

INTERVENTIONS

2 g of metformin (intervention) or placebo (control) from delivery until 1 year postnatally.

PRIMARY OUTCOME MEASURES

Rates of recruitment, randomisation, follow-up, attrition and adherence to the intervention.

SECONDARY OUTCOME MEASURES

Preliminary estimates of glycaemic effects, qualitative exploration, acceptability of the intervention and costs.

RESULTS

Out of 302 eligible women, 57.9% (175/302) were recruited. We randomised 82.3% (144/175) of those recruited, with 71 women in the metformin group and 73 women in the placebo group. Of the participants remaining in the study and providing any adherence information, 54.1% (59/109) took at least 75% of the target intervention dose; the overall mean adherence was 64% (SD 33.6). Study procedures were found to be acceptable to women and healthcare professionals. An increased perceived risk of developing type 2 diabetes, or a positive experience of taking metformin during pregnancy, encouraged participation and adherence to the intervention. Barriers to adherence included disruption to the medication schedule caused by the washout periods ahead of each study visit or having insufficient daily reminders.

CONCLUSIONS

It is feasible to run a full-scale definitive trial on the effectiveness of metformin to prevent type 2 diabetes in women with gestational diabetes, during the early postnatal period. Adherence and engagement with the study could be improved with more regular reminders and potentially the addition of ongoing educational or peer support to reinforce messages around type 2 diabetes prevention.

TRIAL REGISTRATION NUMBER

ISRCTN20930880.

Efficacy of Shenqi Jiangtang Granules-Assisted Western Medicine in the Treatment of Gestational Diabetes Mellitus (GDM)

BACKGROUND

We aimed to investigate the efficacy of Shenqi Jiangtang granules-assisted Western medicine in the treatment of gestational diabetes mellitus (GDM).

METHODS

A total of 147 patients with GDM treated in Qilu Hospital of Shandong University from Jan 2018 to Apr 2019 were enrolled. They were randomly divided into traditional Chinese medicine (TCM) combined with Western medicine group, Western medicine group and control group. The control group was treated with exercise combined with diet therapy, and the Western medicine group was additionally treated with metformin tablets. The TCM combined with Western medicine group was additionally treated with Shenqi Jiangtang granules.

RESULTS

After treatment, the levels of 10 indicators in the three groups were lower than those before treatment (P < 0.05). These indicators were the lowest in the TCM combined with Western medicine group. However, high-density lipoprotein cholesterol (HDL-C), glutathione peroxidase (GSH-PX) and superoxide dismutase (SOD) after treatment increased in the three groups compared with those before treatment (P < 0.05), which was the most obvious in the TCM combined with Western medicine group. After treatment, the number of patients with natural delivery in the TCM combined with Western medicine group was the largest. The incidences of complications in pregnant women, fetuses and newborns were the lowest in the TCM combined with Western medicine group.

CONCLUSION

Application of Shenqi Jiangtang granules-assisted Western medicine in patients with GDM can effectively control blood glucose and lipid levels, enhance antioxidant capacity, reduce the levels of inflammatory cytokines and decrease the incidence of adverse pregnancy outcomes.

Metformin for diabetes prevention: update of the evidence base

We have conducted a narrative review based on a structured search strategy, focusing on the effects of metformin on the progression of non-diabetic hyperglycemia to clinical type 2 diabetes mellitus. The principal trials that demonstrated a significantly lower incidence of diabetes in at-risk populations randomized to metformin (mostly with impaired glucose tolerance [IGT]) were published mainly from 1999 to 2012. Metformin reduced the 3-year risk of diabetes by -31% in the randomized phase of the Diabetes Prevention Program (DPP), vs. -58% for intensive lifestyle intervention (ILI). Metformin was most effective in younger, heavier subjects. Diminishing but still significant reductions in diabetes risk for subjects originally randomized to these groups were present in the trial's epidemiological follow-up, the DPP Outcomes Study (DPPOS) at 10 years (-18 and -34%, respectively), 15 years (-18 and -27%), and 22 years (-18 and -25%). Long-term weight loss was also seen in both groups, with better maintenance under metformin. Subgroup analyses from the DPP/DPPOS have shed important light on the actions of metformin, including a greater effect in women with prior gestational diabetes, and a reduction in coronary artery calcium in men that might suggest a cardioprotective effect. Improvements in long-term clinical outcomes with metformin in people with non-diabetic hyperglycemia ("prediabetes") have yet to be demonstrated, but cardiovascular and microvascular benefits were seen for those in the DPPOS who did not vs. did develop diabetes. Multiple health economic analyses suggest that either metformin or ILI is cost-effective in a community setting. Long-term diabetes prevention with metformin is feasible and is supported in influential guidelines for selected groups of subjects. Future research will demonstrate whether intervention with metformin in people with non-diabetic hyperglycemia will improve long-term clinical outcomes.

Metformin for Preventing Type 2 Diabetes Mellitus in Women with a Previous Diagnosis of Gestational Diabetes: A Narrative Review

Women with a history of gestational diabetes mellitus (GDM) are at greater risk of developing type 2 diabetes mellitus (T2DM) when compared with women who have not had GDM. To delay or prevent T2DM, guidelines recommend regular screening in the primary care setting and lifestyle interventions that are largely focused on dietary and physical activity modifications. As the postpartum period can be challenging for women, uptake and engagement in screening and lifestyle interventions have been poor. Poor uptake and engagement places women with a history of GDM at heightened risk for future morbidity and development of T2DM. Metformin has been a longstanding and safe treatment for the control of blood glucose in people with T2DM. Research has supported the efficacy of metformin, used as an adjunct to a lifestyle intervention or as a stand-alone treatment, in preventing T2DM in people at high risk of T2DM. Findings from longitudinal studies have demonstrated the potential for metformin to reduce conversion to T2DM when used by women with a previous diagnosis of GDM. This review examines the potential effectiveness of metformin to reduce the incidence of T2DM among women with a previous diagnosis of GDM in the "real-world" setting.