Sleep patterns among patients with chronic fatigue: A polysomnography-based study.

OBJECTIVES: The purpose of this study was to detect treatable sleep disorders among patients complaining of chronic fatigue by using sleep questionnaires and polysomnography.

METHODS: Patients were referred to hospital for investigations and rehabilitation because of a suspected diagnosis of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). The criteria for further referral to full-night polysomnography (PSG) were symptoms of excessive daytime sleepiness and/or tiredness in the questionnaires.

RESULTS: Of a total of 381 patients, 78 (20.5%) patients underwent PSG: 66 women and 12 men, mean age 48.6 years, standard deviation ±9.9 years. On the basis of the PSG, 31 (40.3%) patients were diagnosed with obstructive sleep apnoea, 7 (8.9%) patients with periodic limb movement disorder, 32 (41.0%) patients with restless legs syndrome and 54 (69.3%) patients had one or more other sleep disorder. All patients were grouped into those who fulfilled the diagnostic criteria for ME/CFS (n = 55, 70.5%) and those who did not (n = 23, 29.5%). The latter group had significantly higher respiratory (P = .01) and total arousal (P = .009) indexes and a higher oxygen desaturation index (P = .009).

CONCLUSIONS: More than half of these chronic fatigue patients, who also have excessive daytime sleepiness and/or tiredness, were diagnosed with sleep disorders such as obstructive sleep apnoea, periodic limb movement disorder and/or restless legs syndrome. Patients with such complaints should undergo polysomnography, fill in questionnaires and be offered treatment for sleep disorders before the diagnose ME/CFS is set.