Prevalence of insomnia in nurses: a meta-analysis of observational studies using the insomnia severity index

Background Although the prevalence of insomnia in nurses has been extensively studied, reported estimates vary considerably across studies. This meta-analysis of observational studies was conducted to determine the pooled prevalence of insomnia and to explore its potential moderators in nurses. Methods A computerized literature search was conducted in PubMed, Web of Science, Scopus, Embase, Cochrane Library, CINAHL, and PsycINFO from inception to June 2026. A random-effects model was used to generate pooled prevalence estimates, along with 95% confidence intervals and prediction intervals. Heterogeneity was assessed using the I 2 statistic, and subgroup analyses and meta-regression were performed to identify its potential moderators. Results Based on 51 studies from 19 countries encompassing 36,971 participants, the pooled prevalence of insomnia in nurses was 55.0% (95% CI: 49.2–60.8, 95% prediction interval: 15.8–90.8%, I 2 = 99.1%). Subgroup analyses and meta-regression demonstrated that work unit was a significant moderator of the pooled prevalence ( p < 0.001). Conclusion Our findings suggest that over half of nurses experience insomnia, though considerable heterogeneity warrants caution in interpretation. Moreover, work unit was identified as a significant moderator. These findings highlight the urgent need for routine sleep screening and evidence-based interventions to address the high insomnia burden in this occupational group.