Clinical Characteristics Associated With Secondary Generalization in Ocular Myasthenia Gravis Patients: A Systematic Review and Meta-analysis.

Abstract

Ocular myasthenia gravis (OMG) is an autoimmune disorder resulting in ocular symptoms such as diplopia and ptosis. The proportion of patients who convert to secondary generalised myasthenia gravis (SGMG) reported in the literature has been varied. The aim of this systematic review was to determine the clinical characteristics of patients with OMG and determine on the proportion of SGMG conversion. We conducted an electronic database search for randomised controlled trials, prospective non-randomised studies, observational studies and retrospective studies in EMBASE, CENTRAL, MEDLINE and Web of Science. We included studies with patients with OMG who initially presented with ocular symptoms and signs only who were seen in clinical practice, reporting on characteristics and the outcomes of SGMG. We excluded studies with paediatric and congenital myasthenia gravis populations. Eligibile studies included articles written in any language and containing data on patients with OMG. Main outcome measured was the proportion of patients with OMG who converted to SGMG and risk factors associated with secondary generalisation of OMG. Two independent reviewers screened titles and abstracts and extracted data from full texts, reporting findings according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Methodology was evaluated using the Joanna Briggs Institute critical appraisal forms. PROSPERO registration number: CRD2021285257 RESULTS: 31 studies were included in the quantitative and qualitative analysis. The proportion of generalisation ranged from 11 to 84%. The pooled proportion was 39% (95% CI 32%, 47%, I2=95·86%, p<0·001 unweighted, low certainty). Pooled risk ratio of female gender for conversion to SGMG was 1.06 (95%CI 0·96,1·17, I2=0% p=0·614, 21 studies included, very low certainty) and pooled risk ratio of AChR positivity was 1·30 (95%CI 1·05,1·56, I2=0% p=0·455, 16 studies included, very low certainty). Risk factors such as female gender and anti-AChR positivity have been identified as possible associations with SGMG but there are not enough quality observational studies. There is a need for a prospective global database of OMG patients, including all countries with different populations.