The prevalence of severe fatigue in rheumatic diseases: an international study

Fatigue is a common, disabling, and difficult-tomanage
problem in rheumatic diseases. Prevalence estimates
of fatigue within rheumatic diseases vary considerably. Data
on the prevalence of severe fatigue across multiple rheumatic
diseases using a similar instrument is missing. Our aim was to
provide an overview of the prevalence of severe fatigue across
a broad range of rheumatic diseases and to examine its association
with clinical and demographic variables. Online questionnaires
were filled out by an international sample of 6120
patients (88 % female, mean age 47) encompassing 30 different
rheumatic diseases. Fatigue was measured with the
RAND(SF)-36 Vitality scale. A score of ≤35 was taken as
representing severe fatigue (90 % sensitivity and 81 % specificity
for chronic fatigue syndrome). Severe fatigue was present
in 41 to 57 % of patients with a single inflammatory rheumatic
disease such as rheumatoid arthritis, systemic lupus erythematosus,
ankylosing spondylitis, Sjögren’s syndrome,
psoriatic arthritis, and scleroderma. Severe fatigue was least
prevalent in patients with osteoarthritis (35 %) and most prevalent
in patients with fibromyalgia (82 %). In logistic regression
analysis, severe fatigue was associated with having fibromyalgia,
having multiple rheumatic diseases without fibromyalgia,
younger age, lower education, and language (French:
highest prevalence; Dutch: lowest prevalence). In conclusion,
one out of every two patients with a rheumatic disease is
severely fatigued. As severe fatigue is detrimental to the patient,
the near environment, and society at large, unraveling
the underlying mechanisms of fatigue and developing optimal
treatment should be top priorities in rheumatologic research
and practice.