Diet and physical activity in pregnancy to prevent gestational diabetes: A protocol for an individual participant data (IPD) meta-analysis on the differential effects of interventions with economic evaluation

Dyuti Coomar, Jonathan Hazlehurst, Frances Austin, Charlie E M Foster, Graham A Hitman, Nicola Heslehurst, Stamatina Iliodromiti, Ana Pilar Betran Lazaga, Ngawai Moss, Lucilla Poston, Krishnarajah Nirantharakumar, Tracy Roberts, Sharon A Simpson , Helena J Teede, Richard D Riley, John Allotey, Shakila Thangaratinam

Research output: Contribution to journalArticle (Academic Journal)peer-review


Mothers with gestational diabetes (GDM) are at increased risk of pregnancy-related complications and developing type-2 diabetes after delivery. Diet and physical-activity based interventions may prevent GDM, but variations in populations, interventions and outcomes in primary trials have limited the translation of available evidence into practice. We plan to undertake an individual participant data (IPD) meta-analysis of randomised trials to assess the differential effects and cost-effectiveness of diet and physical-activity based interventions in preventing GDM and its complications.
The International Weight Management in Pregnancy Collaborative Network database is a living repository of IPD from randomised trials on diet and physical-activity in pregnancy identified through a systematic literature search. We shall update our existing search on MEDLINE, EMBASE, BIOSIS, LILACS, Pascal, Science Citation Index, CDSR, CENTRAL, DARE and HTA Database without language restriction, to identify relevant trials until March 2021. Primary researchers will be invited to join the Network and share their IPD. Trials including women with GDM at baseline will be excluded. We shall perform a one and two stage random effects meta-analysis for each intervention type (all interventions, diet-based, physical-activity based, and mixed approach), to obtain summary intervention effects on GDM with 95% confidence intervals, and summary treatment-covariate interactions. Heterogeneity will be summarised using I2 and tau2 statistics with 95% prediction intervals. Publication and availability bias will be assessed by examining small-study effects. Study quality of included trials will be assessed by the Cochrane Risk of Bias tool, and the GRADE approach will be used to grade the evidence in the results. A model-based economic analysis will be carried out to assess the cost-effectiveness of interventions to prevent GDM and its complications compared to usual care.
Ethics approval is not required. The study is registered on PROSPERO (CRD42020212884). Results will be submitted for publication in peer-reviewed journals.

Strengths and Limitations
• The IPD meta-analysis builds on an established global group’s (i-WIP) living database (24,766 women, 58 trials) with the potential to expand further with additional published data
• Increased power in IPD compared to aggregate meta-analysis to determine the differential effects of lifestyle interventions on gestational diabetes
• Detailed mapping of the of the intervention components will enable translation of the results to clinical practice.
• Limitations include potential lack of access to new data and missingness in available data.
Original languageEnglish
JournalBMJ Open
Publication statusAccepted/In press - 27 Feb 2021

Structured keywords

  • SPS Exercise, Nutrition and Health Sciences


  • Gestational diabetes mellitus
  • IPD meta-analysis
  • pregnancy
  • diabetes

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