Demographic, clinical, and symptomatic correlates of subjective sleep quality in adults with multiple sclerosis.

Background: This study examined a comprehensive set of demographic, clinical, and symptomatic variables as correlates of subjective sleep quality in adults with multiple sclerosis (MS).

Methods: Participants with MS(N=485) completed the Pittsburgh Sleep Quality Index(PSQI), a demographics and clinical characteristics questionnaire, the Patient Determined Disease Steps Scale(PDDS), the Fatigue Severity Scale, and the Hospital Anxiety and Depression Scale. We conducted bivariate Spearman's rho (ρ) correlation analyses and multiple linear regression analysis for identifying variables associated with PSQI scores.

Results: Participants had a mean (standard deviation) age of 55.4 (12.6) years and were mostly female (78%) with a median [interquartile range] PDDS of 2.0[3.0]. Higher levels of fatigue (ρ=0.32), more symptoms of anxiety (ρ=0.39) and depression (ρ=0.36), younger age (ρ=-0.12), lower income status (ρ=-0.13), shorter MS disease duration (ρ=-0.11), being in a minority group (ρ=0.09), and being unemployed (ρ=-0.10) were associated with worse sleep quality. There were no significant associations between gender, marital status, parental status, education level, disability status, or MS disease type and sleep quality. The overall regression model accounted for 26.3% of variance in sleep quality (F[8,229.8]=20.25) and there were significant coefficients for anxiety(β=0.25), fatigue(β=0.18), depression(β=0.16), and employment status(β=-0.12), but not disease duration, age, race, or income level.

Discussion: Participants with higher levels of anxiety, fatigue, and depression and who were unemployed reported worse sleep quality in our sample of adults with MS. These results may identify specific subgroups of the MS population that experience more sleep problems, and therefore are in greatest need for interventions designed to improve sleep impairment.