Sleep disorders in multiple sclerosis: a case-control study using the São Paulo Epidemiologic sleep study (Episono) database

BACKGROUND: Sleep disorders such as obstructive sleep apnea and restless legs syndrome are prevalent in the general population and patients with chronic diseases such as multiple sclerosis (MS). OBJECTIVES: This study compared the prevalence of sleep disorders complaints, fatigue, depression, and chronotype of adult patients with multiple sclerosis (PwMS) to a representative sample of São Paulo city residents. METHODS: A comparative study was made between PwMS and volunteers from the São Paulo Epidemiologic Sleep Study (Episono) study. We compared the scores of sleep questionnaires using the multivariate analysis of variance (MANOVA) test to evaluate the effects and analysis of variance (ANOVA) as a follow-up test. Covariates were age, sex, and physical activity. The Pearson correlation test was performed to measure the correlation between Expanded Disability Status Scale (EDSS) and the scores of the sleep questionnaires. Finally, we applied propensity score matching to reduce bias in estimating differences between the two groups. Analyses were performed using Stata 14 (StataCorp, College Station, TX, USA) and IBM SPSS Statistics for Windows version 22.0 (IBM Corp., Armonk, NY, USA). RESULTS: The Episono group had worse sleep quality, and more excessive daytime sleepiness than PwMS. Obstructive sleep apnea and restless legs syndrome were more frequent in the Episono group. There was no difference in chronotype between the two groups, with morning and intermediate preference. There was no correlation between EDSS and sleep complaints. Fatigue was intensively present among PwMS. CONCLUSIONS: Disease Modifying Drug (DMD)-treated PwMS had a lower frequency of sleep complaints, no difference in chronotype, and a higher prevalence of fatigue than a sample of São Paulo city residents. The immunomodulatory drugs commonly used to treat MS may have contributed to these findings.