13. september 2003 

Chronic fatigue syndrome.

Clin Evid. 2003 Jun;(9):1172-85.

Reid S, Chalder T, Cleare A, Hotopf M, Wessely S.

St Mary's Hospital, London, UK.

NLM Citation: PMID: 12967415

Overview:

DEFINITION:  Chronic fatigue syndrome (CFS) is characterised by severe,
disabling fatigue and other symptoms, including musculoskeletal pain,
sleep disturbance, impaired concentration, and headaches. Two widely used
definitions of CFS, from the US Centers for Disease Control and
Prevention [1] and from Oxford, UK, [2] were developed as operational
criteria for research (see table 1). There are two important differences
between these definitions. The UK criteria insist upon the presence of
mental fatigue, whereas the US criteria include a requirement for several
physical symptoms, reflecting the belief that CFS has an underlying
immunological or infective pathology.

INCIDENCE/PREVALENCE: Community and primary care based studies have
reported the prevalence of CFS to be 0–3%, depending on the criteria
used. [3] [4] Systematic population surveys have found similar prevalence
of CFS in people of different socioeconomic status, and in all ethnic
groups. [4] [5]

AETIOLOGY: The cause of CFS is poorly understood. Women are at higher
risk than men (RR 1.3- 1.7 depending on diagnostic criteria used).[6]

PROGNOSIS: Studies have focused on people attending specialist clinics. A
systematic review of studies of prognosis (search date 1996) found that
children with CFS had better outcomes than adults: 54-94% of children
showed definite improvement (after up to 6 years' follow up), whereas
20-50% of adults showed some improvement in the medium term and only 6%
returned to premorbid levels of functioning. [7] Despite the considerable
burden of morbidity associated with CFS, we found no evidence of
increased mortality. The systematic review found that outcome was
influenced by the presence of psychiatric disorders (depression and
anxiety), and beliefs about causation and treatment. [7]

AIMS: To reduce levels of fatigue and associated symptoms; to increase
levels of activity; to improve quality of life.

OUTCOMES: Severity of symptoms and their effects on physical function and
quality of life. These outcomes are measured in several different ways:
the medical outcomes survey short form general health survey (SF-36), [8]
a rating scale measuring limitation of physical functioning caused by ill
health (score range 0-100, where 0 = limited in all activities and 100 =
able to carry out vigorous activities); the Karnofsky scale, [9] a
modified questionnaire originally developed for the rating of quality of
life in people undergoing chemotherapy for malignancy; the Beck
Depression Inventory, [10] a checklist for quantifying depressive
symptoms; the sickness impact profile, [11] a measure of the influence of
symptoms on social and physical functioning; the Chalder fatigue scale,
[12] a rating scale measuring subjective fatigue (score range 0-11, where
scores > 4 = excessive fatigue); the clinical global impression scale,
[13] a validated measure of overall change compared with baseline at
study onset, with seven possible scores from "very much worse" (score 7)
to "very much better" (score 1); and self reported severity of symptoms
and levels of activity, the Nottingham health profile [14] contains
questions in 6 categories — energy, pain perception, sleep patterns,
sense of social isolation, emotional reactions, physical mobility
(weighted scores give maximum 100 for answer yes to all questions, and
minimum 0 for someone with no complaints).

METHODS: Clinical Evidence search and appraisal July 2002.

References	

1. Fukuda K, Straus S, Hickie I, et al. The chronic fatigue syndrome: a
comprehensive approach to its definition and study. Ann Intern Med
1994;121:953–959.
2. Sharpe M, Archard LC, Banatvala JE. A report — chronic fatigue
syndrome: guidelines for research. J R Soc Med 1991;84:118–121.
3. Wessely S, Chalder T, Hirsch S, et al. The prevalence and morbidity of
chronic fatigue and chronic fatigue syndrome: a prospective primary care
study. Am J Public Health 1997;87:1449–1455.
4. Steele L, Dobbins JG, Fukuda K, et al. The epidemiology of chronic
fatigue in San Francisco. Am J Med 1998;105(suppl 3A):83–90.
5. Lawrie SM, Pelosi AJ. Chronic fatigue syndrome in the community:
prevalence and associations. Br J Psychiatry 1995;166:793–797.
6. Wessely S. The epidemiology of chronic fatigue syndrome. Epidemiol Rev
1995;17:139–151.
7. Joyce J, Hotopf M, Wessely S. The prognosis of chronic fatigue and
chronic fatigue syndrome: a systematic review. QJM 1997;90:223–133.
Search date 1996; primary sources Medline, Embase, Current Contents, and
Psychlit.
8. Stewart AD, Hays RD, Ware JE. The MOS short-form general health
survey. Med Care 1988;26:724–732.
9. Karnofsky DA, Burchenal JH, MacLeod CM. The clinical evaluation of
chemotherapeutic agents in cancer. New York Academy of Medicine, New
York: Columbia University Press;1949:191–206.
10. Beck AT, Ward CH, Mendelson M, et al. An inventory for measuring
depression. Arch Gen Psychiatry 1961;4:561–571.
11. Bergner M, Bobbit RA, Carter WB, et al. The sickness impact profile:
development and final revision of a health status measure. Med Care
1981;19:787–805.
12. Chalder T, Berelowitz C, Pawlikowska T. Development of a fatigue
scale. J Psychosom Res 1993;37:147–154.
13. Guy W. ECDEU assessment manual for psychopharmacology. Rockville, MD:
National Institute of Mental Health,1976:218–222.
14. Hunt SM, McEwen J, McKenna SP. Measuring health status: a new tool
for clinicians and epidemiologists. J Roy Coll Gen Prac 1985,35:185–188.