Meibomian gland dysfunction and primary Sjögren’s syndrome dry eye: a protocol for systematic review and meta-analysis

INTRODUCTION: Primary Sjögren’s syndrome (pSS) is a systemic autoimmune disorder that primarily affects the exocrine glands such as the lacrimal and the salivary glands. Dry eye disease (DED) is one of the most prevalent manifestations of pSS and is usually classified into aqueous-deficient dry eye and evaporative dry eye. Sjögren’s syndrome dry eye (SSDE) is generally described as aqueous-deficient dry eye. However, as the leading pathophysiological mechanism of evaporative dry eye, meibomian gland dysfunction (MGD) also has influence on SSDE, which has been shown in recent studies. We speculate that SSDE is more than just an aqueous-deficient dry eye. While no related systematic review and meta-analysis has been published, the present study is designed to derive a better understanding of the association between MGD and SSDE. METHODS AND ANALYSIS: The Preferred Reporting items for Systematic Reviews and Meta-Analysis for Protocols 2015 statement was used to prepare this protocol. PubMed, Embase, Web of Science, Cochrane Database, China National Knowledge Infrastructure and Wan Fang Database will be searched from their inception to 31 October 2021, with restrictions to publications in English or Chinese. Two reviewers will independently carry out data extraction and quality assessment. The diagnosis of pSS will meet the standard diagnostic criteria, such as American College of Rheumatology/European League against Rheumatism Classification Criteria (ACR/EULAR) or American-European Consensus Group Classification criteria (AECG), and the definition of MGD and DED will differ between studies. The quality of included studies will be judged using the Newcastle-Ottawa Quality Scale. We will carry out this meta-analysis using RevMan V.5.4.1. The incidence of MGD in patients with SSDE will be indicated as OR with 95% CI. ETHICS AND DISSEMINATION: Ethical approval is not required as this meta-analysis is performed based on published studies and does not involve human participants. The results will be published in a peer-reviewed journal. PROSPERO REGISTRATION NUMBER: CRD42021226017.