From nocturnal awakenings to nocturnal voiding: the relationship between insomnia and nocturia – a systematic review

INTRODUCTION: The aim of this study was to systematically evaluate relevant literature regarding 1) the prevalence of nocturia in patients with insomnia; 2) sleep characteristics of insomniacs with and without nocturia; 3) interventions for the treatment of insomnia and their effect on nocturia. EVIDENCE ACQUISITION: A systematic review of literature was performed through EMBASE, MEDLINE, CLINICALTRIALS.GOV and CENTRAL databases up until November 2022 according to the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) statement. From the identified reports, 11 studies were retained, of which 7 were eligible for meta-analysis. Bias assessment was performed using the ROBINS tools as per the Cochrane collaboration guidelines. EVIDENCE SYNTHESIS: A total of 5396 older adults were included in the meta-analysis. The pooled estimate of the OR was 1.958 (95% CI: 1.609-2.384) for nocturia in patients with insomnia based on 7 studies in a random effects model with nonsignificant heterogeneity (I²=50.83%, P=0.06). Wake after sleep onset (WASO) was longer in people with insomnia and nocturia compared to those without and sleep efficiency (SE) declined. Interventions with melatonin, diet and behavioral therapy were beneficial on nocturia frequency in insomniacs. A limiting factor of our analysis was the scarcity of available data, potentially causing an important selection bias. CONCLUSIONS: The overall odds for nocturia in older adults is higher in patients with insomnia than those without and is associated with worse sleep outcomes. Interventions for treating insomnia such as melatonin, behavioral therapy and diet show beneficial results on nocturnal voiding frequency. We advocate for further research in which uniform definitions and questionnaires are used. Routine screening for nocturia in patients with insomnia could be beneficial to maximize sleep quality improvement.