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.

Myo-inositol nutritional supplement for prevention of gestational diabetes (EMmY): a randomised, placebo-controlled, double-blind pilot trial with nested qualitative study.

OBJECTIVES: To determine the feasibility and acceptability of conducting a randomised trial on the effects of myo-inositol in preventing gestational diabetes in high-risk pregnant women. DESIGN: A multicentre, double-blind, placebo-controlled, pilot randomised trial with nested qualitative evaluation. SETTING: Five inner city UK National Health Service hospitals PARTICIPANTS: Multiethnic pregnant women at 12+0 and 15+6 weeks' gestation with risk factors for gestational diabetes. INTERVENTIONS: 2 g of myo-inositol or placebo, both included 200 µg folic acid, twice daily until delivery. PRIMARY OUTCOME MEASURES: Rates of recruitment, randomisation, adherence and follow-up. SECONDARY OUTCOME MEASURES: Glycaemic indices (including homoeostatic model assessment-insulin resistance HOMA-IR), gestational diabetes (diagnosed using oral glucose tolerance test at 28 weeks and by delivery), maternal, perinatal outcomes, acceptability of intervention and costs. RESULTS: Of the 1326 women screened, 58% (773/1326) were potentially eligible, and 27% (205/773) were recruited. We randomised 97% (198/205) of all recruited women (99 each in intervention and placebo arms) and ascertained outcomes in 90% of women (178/198) by delivery. The mean adherence was 52% (SD 44) at 28 weeks' and 34% (SD 41) at 36 weeks' gestation. HOMA-IR and serum insulin levels were lower in the myo-inositol vs placebo arm (mean difference -0.6, 95% CI -1.2 to 0.0 and -2.69, 95% CI -5.26 to -0.18, respectively). The study procedures were acceptable to women and healthcare professionals. Women who perceived themselves at high risk of gestational diabetes were more likely to participate and adhere to the intervention. The powder form of myo-inositol and placebo, along with nausea in pregnancy were key barriers to adherence. CONCLUSIONS: A future trial on myo-inositol versus placebo to prevent gestational diabetes is feasible. The intervention will need to be delivered in a non-powder form to improve adherence. There is a signal for efficacy in reducing insulin resistance in pregnancy with myo-inositol. TRIAL REGISTRATION NUMBER: ISRCTN48872100.

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 trial­Optimising health outcomes with Metformin to prevent diAbetes After pregnancy (OMAhA).

INTRODUCTION: Up to half of all women diagnosed with gestational diabetes mellitus develop type 2 diabetes within 5 years after delivery. Metformin is effective in preventing type 2 diabetes in high-risk non-pregnant individuals, but its effect when commenced in the postnatal period is not known. We plan to assess the feasibility of evaluating metformin versus placebo in minimising the risk of dysglycaemia including type 2 diabetes after delivery in postnatal women with a history of gestational diabetes through a randomised trial. METHODS AND ANALYSIS: Optimising health outcomes with Metformin to prevent diAbetes After pregnancy (OMAhA) is a multicentre placebo-controlled double-blind randomised feasibility trial, where we will randomly allocate 160 postnatal women with gestational diabetes treated with medication to either metformin (intervention) or placebo (control) tablets to be taken until 1 year after delivery. The primary outcomes are rates of recruitment, randomisation, adherence and attrition. The secondary outcomes are maternal dysglycaemia, cost and quality of life outcomes in both arms, and acceptability of the study and intervention, which will be evaluated through a nested qualitative study. Feasibility outcomes will be summarised using descriptive statistics, point estimates and 95% CIs. ETHICS AND DISSEMINATION: The OMAhA study received ethics approval from the London-Brent Research Ethics Committee (18/LO/0505). Trial findings will be published in a peer-reviewed journal, disseminated at conferences, through our Patient and Public Involvement advisory group (Katie's Team) and through social media platforms. TRIAL REGISTRATION NUMBER: ISRCTN20930880.

Comparing methods for mapping cis acting polymorphisms using allelic expression ratios.

Genome wide association studies frequently reveal associations between disease susceptibility and polymorphisms outside coding regions. Such associations cannot always be explained by linkage disequilibrium with changes affecting the transcription products. This has stimulated the interest in characterising sequence variation influencing gene expression levels, in particular in changes acting in cis. Differences in transcription between the two alleles at an autosomal locus can be used to test the association between candidate polymorphisms and the modulation of gene expression in cis. This type of approach requires at least one transcribed polymorphism and one candidate polymorphism. In the past five years, different methods have been proposed to analyse such data. Here we use simulations and real data sets to compare the power of some of these methods. The results show that when it is not possible to determine the phase between the transcribed and potentially cis acting allele there is some advantage in using methods that estimate phased genotype and effect on expression simultaneously. However when the phase can be determined, simple regression models seem preferable because of their simplicity and flexibility. The simulations and the analysis of experimental data suggest that in the majority of situations, methods that assume a lognormal distribution of the allelic expression ratios are both robust to deviations from this assumption and more powerful than alternatives that do not make these assumptions.