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

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.

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.

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.

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.