Obstructive sleep apnea and fatigue in patients with multiple sclerosis.

STUDY OBJECTIVES: The prevalence of obstructive sleep apnea (OSA) in persons with multiple sclerosis (MS) remains unknown, and little information exists regarding the relative contributions of OSA to symptoms of MS-related fatigue in the presence of other clinical and sleep-related confounders. The objectives of this study were to investigate the prevalence of diagnosed OSA and OSA risk among MS patients, and to assess relationships between fatigue severity, OSA, OSA risk, and sleep quality among persons with MS.

METHODS: N = 195 MS patients completed a questionnaire comprised of items regarding OSA diagnosis, sleep quality and quantity, daytime symptoms, and 4 validated scales: the Epworth Sleepiness Scale, Fatigue Severity Scale, Insomnia Severity Index, and STOP-Bang questionnaire. Medical records were also accessed to examine clinical characteristics that may predict fatigue or OSA risk.

RESULTS: N = 41 patients (21%) carried a formal diagnosis of OSA. N = 110 (56%) of all patients, and 38 (93%) of those with diagnosed OSA had STOP-Bang scores ≥ 3, indicating an elevated OSA risk. In regression models, the most significant predictors of higher FSS scores were higher STOP-Bang scores (p = 0.01), higher number of nocturnal symptoms (p < 0.0001), and higher disability level (p < 0.0001).

CONCLUSIONS: Sleep disturbances, and OSA in particular, may be highly prevalent yet underrecognized contributors to fatigue in persons with MS.