Maternal glucose levels and future risk of developing cardiovascular disease: a systematic review and meta-analysis protocol.

INTRODUCTION: Hyperglycaemia during pregnancy has been considered as one of the risk factors for cardiovascular diseases (CVDs) among women. Although the evidence regarding the association between gestational diabetes mellitus (GDM) and subsequent CVD has been synthesised, there are no systematic reviews covering the evidence of the association among the non-GDM population. This systematic review and meta-analysis, therefore, aim to fill the gap by summarising existing evidence on the association between maternal glucose levels and the risk of future CVD in pregnant women with or without a diagnosis of GDM.

METHODS AND ANALYSIS: This systematic review protocol was reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols guidelines. Comprehensive literature searches were performed in the following electronic databases: MEDLINE, EMBASE and CINAHL to identify relevant papers from inception to 31 December 2022. All observational studies (case-control studies, cohort studies and cross-sectional studies) will be included. Two reviewers will perform the abstract and full-text screening based on the eligibility criteria through Covidence. The Newcastle-Ottawa Scale will be used to assess the methodological quality of included studies. Statistical heterogeneity will be assessed by using the I2 test and Cochrane's Q test. If the included studies are found to be homogeneous, pooled estimates will be calculated and meta-analysis will be performed using Review Manager 5 (RevMan) software. Random effects will be used to determine weights for meta-analysis, if needed. Pre-specified subgroup analysis and sensitivity analysis will be performed, if needed. The study results will be presented in the sequence of main outcomes, secondary outcomes and important subgroup analysis for each type of glucose level separately.

ETHICS AND DISSEMINATION: Given no original data will be collected, ethics approval is not applicable for this review. The results of this review will be disseminated by publication and conference presentation.

PROSPERO REGISTRATION NUMBER: CRD42022363037.