Hypersomnia and Bipolar Disorder: A systematic review and meta-analysis of proportion

Background: Hypersomnia is a common problem amongst individuals with Bipolar Disorder (BD). The objective of this meta-analysis is to estimate the frequency of hypersomnia in individuals with BD, and identify associated factors METHODS: Our search focused on articles documenting the frequency of hypersomnia among individuals with BD indexed in PubMed database and in the Cochrane Library, following the recommendations from the Meta-Analysis Of Observational Studies in Epidemiology (MOOSE) Group. A meta-analysis of proportion was conducted; funnel plot and Egger's test were used for the assessment of publication bias. Subgroups analyses were performed in order to evaluate possible confounders and associated factors.

Results: We identified 10 studies, which included 1824 patients with BD. The overall estimate of the proportion of BD cases that reported hypersomnia was 29.9% [95% confidence interval (CI): 25.8 - 34.1%, I² = 59.2%; p < .05]. The funnel plot and the Egger's test suggest a low risk of publication bias (p = .527). The polarity of mood state, Bipolar Disorder type, use of medication, age, diagnostic criteria and hypersomnia criteria were not significantly related to hypersomnia.

Limitations: There is a possibility that smaller cross-sectional studies were not included. The high heterogeneity between studies is frequent in meta-analysis of both interventional and observational studies. Hypersomnia was not the primary outcome in some of the included studies.

Conclusions: To our knowledge, this is the first systematic review and meta-analysis of hypersomnia prevalence in patients with BD. Further studies focused on clinical correlates and implications for health outcomes in BD are warranted.