Association between visual impairment and risk of suicide: Protocol for a systematic review and meta-analysis

INTRODUCTION: Suicide is an important public health problem. Well-established risk factors of suicide include depression, family history of mental disorders, substance problem, chronic physical illness, and others. Sensory impairment, especially visual impairment (VI), has a critical impact on both mental and physical health. However, the association between VI and risk of suicide has not been thoroughly investigated and remains controversial. Our aim is to systematically review and meta-analyze the current evidence on the association between VI and risk of suicide and to evaluate the direction and magnitude of the association. METHODS AND ANALYSIS: We aim to search PubMed, EMBASE and the Cochrane Library to identify all population-based studies on the association between VI and risk of suicide. Two reviewers will independently conduct study selection, data extraction and risk of bias (ROB) assessment. The Newcastle-Ottawa scale will be applied to evaluate the methodologic quality of the included studies for ROB assessment. The primary outcome measure will be the relative risk (RR) of suicide, and the secondary outcome measures will be the risks of suicidal ideation (SI) and suicide attempt (SA). Estimates of risk with 95% confidence intervals (CIs) for suicide, SI and SA, respectively, will be calculated and summarized. We will perform random-effects meta-analyses to combine the pooled effects. Meta-regression will be applied to investigate the effects of multiple factors across studies. Subgroup and sensitivity analyses will be conducted for screening of any potential sources of heterogeneity. Publication bias will be evaluated by funnel plot and Begg and Mazumdar correlation testing. The body of evidence will be assessed using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. CONCLUSION: This article presents a study protocol for investigating the association between VI and risk of suicide. The findings of this study will contribute to our current knowledge of the impact of VI as a risk factor of suicide. In addition, meta-regression and subgroup analyses will provide further insights to factors affecting the association between VI and suicide risk. TRIAL REGISTRATION: Systematic review registration: PROSPERO CRD 42022325106.