Undiagnosed and comorbid disorders in patients with presumed chronic fatigue syndrome

Abstract

Objective: To assess undiagnosed and comorbid disorders in patients referred to a tertiary care center with a presumed diagnosis of chronic fatigue syndrome (CFS).

Methods: Patients referred for chronic unexplained fatigue entered an integrated diagnostic pathway, including internal medicine assessment, psychodiagnostic screening, physiotherapeutic assessment and polysomnography+multiple sleep latency testing. Final diagnosis resulted from a multidisciplinary team discussion. Fukuda criteria were used for the diagnosis of CFS, DSM-IV-TR criteria for psychiatric disorders, ICSD-2 criteria for sleep disorders.

Results: Out of 377 patients referred, 279 (74.0%) were included in the study [84.9% female; mean age 38.8years (SD 10.3)]. A diagnosis of unequivocal CFS was made in 23.3%. In 21.1%, CFS was associated with a sleep disorder and/or psychiatric disorder, not invalidating the diagnosis of CFS. A predominant sleep disorder was found in 9.7%, 19.0% had a psychiatric disorder and 20.8% a combination of both. Only 2.2% was diagnosed with a classical internal disease. In the total sample, a sleep disorder was found in 49.8%, especially obstructive sleep apnea syndrome, followed by psychophysiologic insomnia and periodic limb movement disorder. A psychiatric disorder was diagnosed in 45.2%; mostly mood and anxiety disorder.

Conclusions: A multidisciplinary approach to presumed CFS yields unequivocal CFS in only a minority of patients, and reveals a broad spectrum of exclusionary or comorbid conditions within the domains of sleep medicine and psychiatry. These findings favor a systematic diagnostic approach to CFS, suitable to identify a wide range of diagnostic categories that may be subject to dedicated care.

Keywords: AASM; AHI; American Academy of Sleep Medicine; BMI; CDC; CFS; Centers for Disease Control and Prevention; Chronic fatigue syndrome; Comorbidity; DSM-IV-TR; Diagnostic and Statistical Manual of Mental Disorders, 4th edition — text revision; ICSD-2; International Classification of Sleep Disorders, 2nd edition; MSLT; MUS; OSA; PLM; PLMD; PSG; Prevalence; Psychiatric disorders; REM; SD; Sleep disorders; UCF; apnea-hypopnea index; body mass index; chronic fatigue syndrome; medically unexplained symptoms; multiple sleep latency test; obstructive sleep apnea; periodic limb movement disorder; periodic limb movements; polysomnography; rapid eye movements; standard deviation; unexplained chronic fatigue.