Correlation between masked hypertension and endothelial dysfunction measured by flow-mediated dilation: a protocol of systematic review and meta-analysis

INTRODUCTION: A surrogate marker to evaluate artery endothelial response when stimulated by reactive hyperaemia, known as brachial flow-mediated dilation (FMD), has prognostic value in predicting hypertensive organ damage and cardiovascular disease events. However, the degree of correlation between brachial FMD and masked hypertension (MH) outcomes is still unclear. Therefore, the purpose of this study is to pool data regarding FMD with respect to MH. METHODS AND ANALYSIS: Electronic databases MEDLINE, EMBASE, China National Knowledge Infrastructure and Cochrane Library will be searched for the following keywords: endothelial dysfunction, flow-mediated dilation, and masked hypertension, masked uncontrolled hypertension (MUCH) and prehypertension. The following are the eligibility criteria: population—adults (18 years old or older) without hypertension at baseline, with suspected endothelial dysfunction, or from MH/MUCH populations (office blood pressure <140/90 mm Hg and home blood pressure ≥135 mm Hg and/or 85 mm Hg) and from controlled clinical trials, cohort studies, or randomised and controlled trials; exposures—any metrics for FMD; comparisons—participants without MH or MUCH; and outcome—change in FMD between the case group and the control group. Two authors will be engaged in screening and collecting data independently; disagreements will be resolved through discussion. Data extraction will include primary data designated as HR, OR, correlations and regression coefficients. Comprehensive Meta-Analysis V.2.0 will be used to conduct related subgroup and sensitivity analyses and publication bias. ETHICS AND DISSEMINATION: This study does not require ethics approval. It will be submitted to a peer-reviewed journal. PROSPERO REGISTRATION NUMBER: CRD42020208362.