Insomnia, Fatigue, Bladder Disorders and Mood Disorders among Polish Patients with Multiple Sclerosis: Cross-Sectional Study

Background: To investigate the prevalence of sleep disorders in patients with multiple sclerosis (PwMS) in comparison to healthy controls (HCs), we aim to explore the correlation between sleep disorders and fatigue, bladder dysfunction, mood disorders in PwMS. Methods: This study involved 175 PwMS and 115 HCs. We conducted a self-administered survey using questionnaires (the authors' questionnaire, the Athens Insomnia Scale (AIS), the Epworth Sleepiness Scale (ESS), the Modified Fatigue Impact Scale (MFIS), the Fatigue Severity Scale (FSS), the Hospital Anxiety and Depression Scale (HADS), and the Numerical Rating Scale (NRS). The neurological disability was determined using Expanded Disability Status Scale. Logistic regression was used to estimate odds ratios (ORs) with 95% confidence intervals (CIs). Results: According to AIS, insomnia was found in 20.6% of PwMS compared to 9.6% of HCs (p < 0.001). Comparing female and male PwMS, we observed that insomnia was more prevalent among female PwMS (25.95% vs. 4.55%, respectively, p < 0.05). Excessive daytime sleepiness was more prevalent in female PwMS (p < 0.05). Female PwMS were more fatigue based on the FSS and the MFIS (p < 0.05). Bladder disorders were observed in 39.43% of PwMS and were significantly linked to MS (p < 0.001). Sleep disturbances were associated with anxiety disorders (OR = 0.22, 95% CI 0.12-0.32 p < 0.001), bladder dysfunction (OR = 0.52 95% CI 0.16-0.87 p < 0.05), and female gender (OR = 0.49, 95% CI 0.037-0.94 p < 0.05). Conclusions: Insomnia is prevalent among PwMS. Our study revealed independent predictors of sleep disturbances among PwMS: female gender, bladder disorders, and anxiety.