Longitudinal changes in sleep quality, and their predictors in patients with multiple sclerosis

Sleep disturbances are common among patients with multiple sclerosis (PwMS), yet their longitudinal course and clinical determinants remain unclear. Here, we aimed to examine sleep quality in PwMS, investigate its association with quality of life, and evaluate its trajectory and clinical predictors over time. Between September 2022 and September 2023, PwMS who had not experienced a recent clinical relapse (within ≤ 2 months) were prospectively recruited. Sleep quality at baseline and after 6-12 months was measured using the Pittsburgh Sleep Quality Index (PSQI). Clinical factors associated with PSQI scores, and their longitudinal trajectories, were examined. A total of 118 patients with MS (median age, 46 years) were enrolled, with 54% identified as poor sleepers (PSQI > 5) at baseline and a comparable prevalence (53%) at follow-up. Poor sleep quality was associated independently with reduced quality of life. While PSQI scores remained generally stable over time in participants without clinical relapses during follow-up (n = 114), 23 (20.2%) exhibited a marked deterioration in sleep quality (PSQI score increase ≥ 3). Baseline optic Functional Systems scores (baseline: β = 0.226 (95% confidence interval, 0.021, 1.115), follow-up: β = 0.233, (0.038, 1.311)) and depression (baseline: β = 0.261, (1.031, 5.822), follow-up: β = 0.215, (0.473, 5.935)) independently predicted both baseline and future PSQI scores. In conclusion, poor sleep quality is common and persistent in PwMS, with depression and the severity of optic dysfunction identified as key predictors. These findings emphasize the need for targeted sleep management in MS care.