Bipolar disorder and the risk for stroke incidence and mortality: a meta-analysis

Objective Bipolar disorder (BD) may be associated with an increased risk of stroke, but to date, the results of the studies are still controversial. This study aimed to assess the association of BD with stroke incidence and mortality by a meta-analysis. Method PubMed, EMBASE, the Cochrane library databases, and Web of Science databases were searched from inception to July 2020. We regarded stroke as a composite endpoint. The pooled hazard ratio (HRs) of 95% confidence interval (Cls) was calculated. Subgroup and sensitivity analyses were performed to assess the potential sources of heterogeneity of the pooled estimation. Results A total of 7 studies involving a total of 13,305,007 participants were included in this meta-analysis. Pooled analysis showed participants with BD experienced a significantly increased risk of both stroke incidence (combined HR, 1.43; 95% CI, 1.24–1.66; p = 0.000) and stroke mortality (combined HR, 1.54; 95% CI, 1.09–2.18; p = 0.013) compared to participants without BD. In addition, the pooled estimate of multivariate HRs of stroke incidence and mortality were 1.35 (95% CI: 1.26–1.45); 2.30 ( 95% CI: 1.37–3.85) among men and 1.43 (95% CI:1.27–1.60); 2.08 (95% CI:1.60–2.71) among women respectively. Conclusions This meta-analysis suggests that BD may modestly increase the risk of both stroke incidence and mortality. Extensive clinical observational studies should be conducted in the future to explore whether BD is a potentially modifiable risk factor for stroke.